Titanium Valves TiB MMC
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Titanium Valves TiB MMC
Toyota is using a new composite Titanium Boron metal matrix composite for intake and exhaust valves on the Altezza.
Does anybody know if this is available in Vette size valves?
http://www.ml.afrl.af.mil/publicatio...loy_TechFS.pdf
http://www4.builderonline.com/guide/...5&channelID=69
The Automotive Application of Discontinuously Reinforced TiB-Ti Composites
In 1998, Toyota Motor Corporation adopted Intake valves and exhaust valves made of titanium-based alloys for the engine of its Altezza. Both valves were manufactured via a newly developed cost- effective powder metallurgy process. The exhaust valve is made of a newly developed titanium metal-matrix composite (MMC). The valve has achieved sufficient durability and reliability with a manufacturing cost acceptable for the mass-produced automobile engine components.
INTRODUCTION
It is common knowledge that titanium alloys offer outstanding specific strength and corrosion resistance, and they are essential for a variety of aeronautical, aerospace, marine, and military applications. These materials have also been commonly used in racing cars for 30 years. However, titanium alloys are unlikely to be used in mass-produced family automobiles until their cost/performance becomes competitive with that of steel.1 Even assuming the optimum performance of current titanium alloys, it is unlikely they will find application if the cost exceeds double that of steel components. Furthermore, it should be noted that the practical application of titanium alloy components in the automotive industries has been restricted by inferior wear resistance, rigidity, and/or heat resistance.
The blended elemental (BE) P/M method is potentially the lowest- cost process for manufacturing titanium components. The process has a noteworthy advantage over the conventional ingot process in that it enables the production of complex materials that are difficult to make via ingot metallurgy. A cost-saving process and alloys with superior performance are needed for titanium components to be applied to mass-produced automobiles.
In October 1998, a new mass-produced family car equipped with titanium engine valves was released by Toyota Motor Corporation.2 Both valves (intake and exhaust) were manufactured via a newly developed cost-effective P/M forging process. The exhaust valve is made of a unique titanium metalmatrix composite (DR-Ti), specially designed for mechanical properties at elevated temperatures up to 1,150 K. This paper describes the DR-Ti valve development project that started in the mid-1980s.
Figure 1. The processing steps for P/M titanium components via the blended elemental process.
Figure 2. The basic factors in selecting the reinforcing particle and matrix alloy for the metal-matrix composite.
TiB-Ti MMC DEVELOPMENT
Generally, 21-4N steel, which is known as heat-resistant steel, is used in the exhaust valve of automobile engines. This material offers an excellent balance of characteristics including static strength, fatigue property, creep resistance, and oxidation resistance at room temperature and elevated temperature (up to 1,150 K). Cost-effectiveness is needed for a titanium alloy to compete with this material in an exhaust valve.
A feasibility study found that a titanium alloy valve would be able to compete with one of heat-resistant steel if the be method was applied to the valve. This manufacturing process could realize a greater cost reduction than the conventional cast and forge method by reducing raw material cost, improving material yield, and reducing processing steps. Figure 1 shows the general processing steps of the be method.
Pre-supposing that the be method is to be used with a high- temperature sintering operation at approximately 1,600 K, the following conditions are needed to create the ideal reinforcing compound to improve titanium alloy properties: high specific strength, hardness, heat resistance, and rigidity; thermodynamic stability in the titanium alloy at the sintering temperature; insolubility of the elements comprising the reinforcing compound in the titanium matrix and the titanium atoms in the reinforcing compound (mutual solubility minimum); crystallographic stable matrix/ particle boundary; and minimum difference in thermal expansion between the matrix titanium alloy and the reinforcing compound (Figure 2).
In the 1980s, none of the existing reinforcing compounds met all these conditions simultaneously. Therefore, the authors searched for a new reinforcing compound and found the optimum compound to be titanium monoboride (TiB),3-7 which is thermodynamically superior to existing reinforcing compounds such as TiC, SiC, TiB^sub 2^, B^sub 4^C, Al^sub 3^O^sub 4^, TiN, and Si^sub 3^N^sub 4^. Not only was TiB outstanding in all physical and mechanical properties, its linear coefficient of thermal expansion was approximately the same as that of titanium alloy.
Table I compares the properties of reinforcing compound candidates for titanium-based MMC. While TiB is stable in titanium alloys, it is unstable by itself and cannot be treated in powder form. Therefore, pure boron powder or several boride powders must be used as the boron source. These powders react with titanium powder during sintering to form thermodynamically stable TiB particles throughout the titanium alloy matrix with a highly crystallographic coherency at the inter-phase boundary, as shown in Figure 3. This patented material possesses a breakthrough capability not seen in conventional titanium alloys. A typical example is shown in Figure 4, indicating mechanical properties of a developed beta-titanium matrix MMC (20 vol.% TiB/Ti-7Mo-4Fe-2Al-2V).7
Figure 5. The processing steps for the blended elemental Ti-MMC valve production.
Table I. Adaptability of the Reinforcement Particle for B/E Titanium MMC
Figure 3. The microstructure of the developed discontinuous TiB- reinforced titanium matrix MMC made by the be process (10 vol.% TiB/ Ti-6Al-4V-2Mo-1Fe).
Figure 4. The mechanical properties of the developed TiB- particle-reinforced beta matrix Ti-MMC (20 vol.% TiB/Ti-7Mo-4Fe-2Al- 2V).
The synergistic effects of the heat-resistant matrix alloy and the reinforcement particles (TiB) achieve excellent mechanical properties at an elevated temperature up to 1,100 K. The composition of the matrix alloy was determined as Ti-6Al-4Sn-4Zr-1Nb-1Mo-0.2Si- 0.3O for optimal high-temperature creep, fatigue, and oxidation resistances. For optimal ductility, hot formability, and machinability, which, in addition to heal resistance, are essential to component production, the amount of TiB particle was determined to be 5 vol.%.2
Figure 6. The changes in mechanical properties of the developed Ti-MMC with TiB particle content at room temperature and elevated temperature.
Ti-MMC EXHAUST VALVE MANUFACTURING PROCESS
Figure 5 shows the manufacturing steps of the developed TiB-Ti MMC valve. For the raw titanium powder, titanium-hydride powder was used. Titanium-hydride powder is more cost-effective than hydride- dehydride titanium powder and also offers ease of metal die compaction (less adherence). For the strengthening alloying elements, a master-alloy powder of Al-25Sn-25Zr-6Nb-6Mo-1.2Si was prepared by an inert-gas atomization method. TiB^sub 2^ powder was used as the boron source to form in-situ TiB particles.
Table II. Comparison of Mechanical Properties of the Developed Ti- MMC and 21-4N Heat Resistant Steel
The prescribed amount of each material was mixed in a high- energy ball mill. After metal die compaction into a column of approximately 16 mm 40 mm at a pressure of 490 MPa, vacuum sintering at 1,573 K was conducted upon the compact and a sintered billet was prepared for hot forming. Next, induction heating was conducted at around 1,473 K to extrude the valve stem, followed by hot forging for the valve face. After correction of bending of the stem part, an annealing treatment to control the microstructure was performed. An oxidation treatment at 1,100 K for 1.8 ks in air was performed after machining for the final dimension. The thin oxide scale was removed by shot blasting, resulting in wear resistance for the oxygen-solution-hardened surface.
MECHANICAL PROPERTIES OF THE HEAT-RESISTANT Ti-MMC
Figure 6 shows the effects of TiB particles on mechanical properties at room and elevated temperatures. As seen, all of the dynamic as well as the static strength from room temperature to elevated temperature are improved as the TiB particle content increases. Notably, the effect the TiB particle exerted upon fatigue strength at 1,223 K-an essential property for an exhaust valve- exceeds 21-4N steel even at compounding of 5 vol.% TiB.
On the other hand, creep deflection by a simple plumb bob method at 1,073 K tends to increase as the TiB particle amount increases. The creep resistance decrease is believed to result as the matrix alpha phase becomes liner and equiaxcd concomitantly with increasing TiB particle volume. A similar creep abnormity has recently been reported by K. Kawabata.8 A curious composite weakening occurs at a critical creep strain rate lower than the diffusion accommodation rate in theTiB-Ti MMC. In any case, the TiB particle amount has little effect on creep resistance, and the composite exhibits better creep resistance than the 21-4N steel even with 10 vol.% TiB. Although the room-temperature ductility of 3-5% is mostly constant independent of TiB particle content, the high-temperature ductility is notably affected, increasing sharply with even a small amount of TiB particle content. After reaching the maximum value of approximately 13%with the addition of 5 vol.% TiB particle, high- temperature ductility remains at approximately 10% with the addition of 10 vol.% of the TiB particle.
Figure 7. (a) The first family car to feature a Ti-MMC valve and (b) the appearance of the developed valves.
Figure 8. Ti-MMC automobile components (prototype) made by the blended elemental P/M process.
The high-temperature creep resistance can be improved by growing the matrix microstructure, but the beta grain growth invites a decrease in the high-temperature fatigue property and ductility. Therefore, the optimal particle volume should be determined from the point of view of compatibility of the sufficient high-temperature creep resistance, high-temperature fatigue property, and ductility of the exhaust valve. Taking into account all these properties and productivity, the optimal amount of TiB particle was determined to be 5 vol.%
Table II compares the mechanical properties of the developed TiB- Ti MMC and the 21-4N steel at room and elevated temperatures.
ENGINE VALVE PERFORMANCE
Figure 7 shows the developed valves. The intake valve was also made from a titanium-based alloy manufactured via the same cost- effective process as that for the exhaust valve, but it used the conventional Ti-6Al-4V alloy since it does not require as much heat. The developed P/M process resulted in a cost reduction, enabling the application of lightweight titanium valves.
A new engine in which the developed valves were installed, when compared with the conventional steel-valve engine, had a 40% lighter valve weight and 16% lighter valve spring weight. As a result, the maximum revolutions increased by 700 rpm, and the noise in the high- revolution range decreased by 30%. Moreover, the reduction of friction reduced camshaft driving torque by 20%, and high performance and low fuel consumption were achieved.
CONCLUSION
Figure 8 shows examples of prototype DR-Ti MMC components manufactured by the be process. The new material presented in this report has the potential to fundamentally overturn the concept of cost/performance of conventional titanium alloys, and the author believes it may represent a breakthrough in the application of titanium to mass-produced automobiles.
More than 500,000 P/M Ti-MMC valves have been put into the market since 1998; however, production expansion has been delayed. The main reason for the stagnation is cost. Although this valve is cheaper than others made of titanium, it is still about twice as expensive as the current steel valve. Titanium automobile components will never find practical application unless they can compete in cost/ performance with steel components. The greatest production cost reduction would result by eliminating post-sinter processing such as hot-extruding, hot-forging, heat-treating, and machining. The post- sinter processing cost exceeds 60% of the total cost for the products. The author believes that development of a true dense precision forming technology by means of metal-die compaction with pressure-less sintering is the ultimate goal for generalizing the DR- Ti MMC automobile components.9,10
References
1. F.H. Froes, D. Eylon, and H. Bomberger, editors, Titanium Technology: Present Status and Future Trends (Dayton, OH: TDA, 1985).
2. T. Yamaguchi, T. Furuta, and T. Saito, "Development of P/M Titanium Engine Valve," SAE Technical Paper 01-0905 (Warrendale, PA: SAE, 2000).
3. T. Saito and T. Furuta, "Titanium Alloy Matrix Composite by Reaction Sintering," Current Advances in Materials and Processes (Tokyo: Iron & Steel Institute of Japan, 1991), p. 1740.
4. T. Saito et al., "A New Low Cost MMC of TiB Particle Dispersed in Titanium Alloy," Proc. Conf. 1993 Powder Met. World Congress, ed. Y. Bando and L. Kosuge (Kyoto, Japan: JPMA-JSPM, 1993), pp. 642- 645.
5. T. Saito, T. Furuta, and T. Yamaguchi, "Development of Low- Cost Titanium Matrix Composite," Recent Advances in Titanium Metal Matrix Composites, ed. F.H. Froes and J. Storer (Warrendale, PA: TMS, 1995), pp. 33-44.
6. T. Saito, "A Low-Cost P/M Titanium Matrix Composite for Automobile Use, "Advanced Performance Materials, 2 (1995), pp. 121- 144.
7. T. Saito, H. Takamiya, and T. Furuta, "Thermomechanical Properties of P/M beta Titanium Metal Matrix Composite," Material Science and Engineering, A243 (1998), pp. 273-278.
8. K. Kawabata, E. Sato, and K. Kuribayashi, "Composite Weakening and Strengthening of Ti/TiB(w) Composites During Steady State Creep at High Temperature in the Beta Matrix Region," Scripta Materialia, 50 (2004), pp. 523-527.
9. T. Saito, "New Titanium Products via Powder Metallurgy Process," Proc. Cont. Wtb World Conference on Titanium, ed. G. Lutjering (Hamburg, Germany: DGM, 2003), in press.
10. H. Takamiya, M. Kondoh, and T. Saito, "Ultra-High Pressure Warm Compaction for P/M Titanium Components," Cost-Affordable Titanium, ed. FH. Froes, M. Ashraf, and D. Fray (Warrendale, PA: TMS, 2004), pp. 185-192.
Takashi Saito is director of the Materials Department at Toyota Central Research and Development Laboratories in Aichi, Japan.
For more information, contact Takashi Saito, Toyota Central Research and Development Laboratories, Materials Department, 41-1 Yokomichi Nagakute Aichi, 480-1192 Japan; 011-81-561-63-3090; fax 011-81-561-63-5441; e-mail saito@mosk.tytlabs.co.jp.
Copyright Minerals, Metals & Materials Society May 2004
Does anybody know if this is available in Vette size valves?
http://www.ml.afrl.af.mil/publicatio...loy_TechFS.pdf
http://www4.builderonline.com/guide/...5&channelID=69
The Automotive Application of Discontinuously Reinforced TiB-Ti Composites
In 1998, Toyota Motor Corporation adopted Intake valves and exhaust valves made of titanium-based alloys for the engine of its Altezza. Both valves were manufactured via a newly developed cost- effective powder metallurgy process. The exhaust valve is made of a newly developed titanium metal-matrix composite (MMC). The valve has achieved sufficient durability and reliability with a manufacturing cost acceptable for the mass-produced automobile engine components.
INTRODUCTION
It is common knowledge that titanium alloys offer outstanding specific strength and corrosion resistance, and they are essential for a variety of aeronautical, aerospace, marine, and military applications. These materials have also been commonly used in racing cars for 30 years. However, titanium alloys are unlikely to be used in mass-produced family automobiles until their cost/performance becomes competitive with that of steel.1 Even assuming the optimum performance of current titanium alloys, it is unlikely they will find application if the cost exceeds double that of steel components. Furthermore, it should be noted that the practical application of titanium alloy components in the automotive industries has been restricted by inferior wear resistance, rigidity, and/or heat resistance.
The blended elemental (BE) P/M method is potentially the lowest- cost process for manufacturing titanium components. The process has a noteworthy advantage over the conventional ingot process in that it enables the production of complex materials that are difficult to make via ingot metallurgy. A cost-saving process and alloys with superior performance are needed for titanium components to be applied to mass-produced automobiles.
In October 1998, a new mass-produced family car equipped with titanium engine valves was released by Toyota Motor Corporation.2 Both valves (intake and exhaust) were manufactured via a newly developed cost-effective P/M forging process. The exhaust valve is made of a unique titanium metalmatrix composite (DR-Ti), specially designed for mechanical properties at elevated temperatures up to 1,150 K. This paper describes the DR-Ti valve development project that started in the mid-1980s.
Figure 1. The processing steps for P/M titanium components via the blended elemental process.
Figure 2. The basic factors in selecting the reinforcing particle and matrix alloy for the metal-matrix composite.
TiB-Ti MMC DEVELOPMENT
Generally, 21-4N steel, which is known as heat-resistant steel, is used in the exhaust valve of automobile engines. This material offers an excellent balance of characteristics including static strength, fatigue property, creep resistance, and oxidation resistance at room temperature and elevated temperature (up to 1,150 K). Cost-effectiveness is needed for a titanium alloy to compete with this material in an exhaust valve.
A feasibility study found that a titanium alloy valve would be able to compete with one of heat-resistant steel if the be method was applied to the valve. This manufacturing process could realize a greater cost reduction than the conventional cast and forge method by reducing raw material cost, improving material yield, and reducing processing steps. Figure 1 shows the general processing steps of the be method.
Pre-supposing that the be method is to be used with a high- temperature sintering operation at approximately 1,600 K, the following conditions are needed to create the ideal reinforcing compound to improve titanium alloy properties: high specific strength, hardness, heat resistance, and rigidity; thermodynamic stability in the titanium alloy at the sintering temperature; insolubility of the elements comprising the reinforcing compound in the titanium matrix and the titanium atoms in the reinforcing compound (mutual solubility minimum); crystallographic stable matrix/ particle boundary; and minimum difference in thermal expansion between the matrix titanium alloy and the reinforcing compound (Figure 2).
In the 1980s, none of the existing reinforcing compounds met all these conditions simultaneously. Therefore, the authors searched for a new reinforcing compound and found the optimum compound to be titanium monoboride (TiB),3-7 which is thermodynamically superior to existing reinforcing compounds such as TiC, SiC, TiB^sub 2^, B^sub 4^C, Al^sub 3^O^sub 4^, TiN, and Si^sub 3^N^sub 4^. Not only was TiB outstanding in all physical and mechanical properties, its linear coefficient of thermal expansion was approximately the same as that of titanium alloy.
Table I compares the properties of reinforcing compound candidates for titanium-based MMC. While TiB is stable in titanium alloys, it is unstable by itself and cannot be treated in powder form. Therefore, pure boron powder or several boride powders must be used as the boron source. These powders react with titanium powder during sintering to form thermodynamically stable TiB particles throughout the titanium alloy matrix with a highly crystallographic coherency at the inter-phase boundary, as shown in Figure 3. This patented material possesses a breakthrough capability not seen in conventional titanium alloys. A typical example is shown in Figure 4, indicating mechanical properties of a developed beta-titanium matrix MMC (20 vol.% TiB/Ti-7Mo-4Fe-2Al-2V).7
Figure 5. The processing steps for the blended elemental Ti-MMC valve production.
Table I. Adaptability of the Reinforcement Particle for B/E Titanium MMC
Figure 3. The microstructure of the developed discontinuous TiB- reinforced titanium matrix MMC made by the be process (10 vol.% TiB/ Ti-6Al-4V-2Mo-1Fe).
Figure 4. The mechanical properties of the developed TiB- particle-reinforced beta matrix Ti-MMC (20 vol.% TiB/Ti-7Mo-4Fe-2Al- 2V).
The synergistic effects of the heat-resistant matrix alloy and the reinforcement particles (TiB) achieve excellent mechanical properties at an elevated temperature up to 1,100 K. The composition of the matrix alloy was determined as Ti-6Al-4Sn-4Zr-1Nb-1Mo-0.2Si- 0.3O for optimal high-temperature creep, fatigue, and oxidation resistances. For optimal ductility, hot formability, and machinability, which, in addition to heal resistance, are essential to component production, the amount of TiB particle was determined to be 5 vol.%.2
Figure 6. The changes in mechanical properties of the developed Ti-MMC with TiB particle content at room temperature and elevated temperature.
Ti-MMC EXHAUST VALVE MANUFACTURING PROCESS
Figure 5 shows the manufacturing steps of the developed TiB-Ti MMC valve. For the raw titanium powder, titanium-hydride powder was used. Titanium-hydride powder is more cost-effective than hydride- dehydride titanium powder and also offers ease of metal die compaction (less adherence). For the strengthening alloying elements, a master-alloy powder of Al-25Sn-25Zr-6Nb-6Mo-1.2Si was prepared by an inert-gas atomization method. TiB^sub 2^ powder was used as the boron source to form in-situ TiB particles.
Table II. Comparison of Mechanical Properties of the Developed Ti- MMC and 21-4N Heat Resistant Steel
The prescribed amount of each material was mixed in a high- energy ball mill. After metal die compaction into a column of approximately 16 mm 40 mm at a pressure of 490 MPa, vacuum sintering at 1,573 K was conducted upon the compact and a sintered billet was prepared for hot forming. Next, induction heating was conducted at around 1,473 K to extrude the valve stem, followed by hot forging for the valve face. After correction of bending of the stem part, an annealing treatment to control the microstructure was performed. An oxidation treatment at 1,100 K for 1.8 ks in air was performed after machining for the final dimension. The thin oxide scale was removed by shot blasting, resulting in wear resistance for the oxygen-solution-hardened surface.
MECHANICAL PROPERTIES OF THE HEAT-RESISTANT Ti-MMC
Figure 6 shows the effects of TiB particles on mechanical properties at room and elevated temperatures. As seen, all of the dynamic as well as the static strength from room temperature to elevated temperature are improved as the TiB particle content increases. Notably, the effect the TiB particle exerted upon fatigue strength at 1,223 K-an essential property for an exhaust valve- exceeds 21-4N steel even at compounding of 5 vol.% TiB.
On the other hand, creep deflection by a simple plumb bob method at 1,073 K tends to increase as the TiB particle amount increases. The creep resistance decrease is believed to result as the matrix alpha phase becomes liner and equiaxcd concomitantly with increasing TiB particle volume. A similar creep abnormity has recently been reported by K. Kawabata.8 A curious composite weakening occurs at a critical creep strain rate lower than the diffusion accommodation rate in theTiB-Ti MMC. In any case, the TiB particle amount has little effect on creep resistance, and the composite exhibits better creep resistance than the 21-4N steel even with 10 vol.% TiB. Although the room-temperature ductility of 3-5% is mostly constant independent of TiB particle content, the high-temperature ductility is notably affected, increasing sharply with even a small amount of TiB particle content. After reaching the maximum value of approximately 13%with the addition of 5 vol.% TiB particle, high- temperature ductility remains at approximately 10% with the addition of 10 vol.% of the TiB particle.
Figure 7. (a) The first family car to feature a Ti-MMC valve and (b) the appearance of the developed valves.
Figure 8. Ti-MMC automobile components (prototype) made by the blended elemental P/M process.
The high-temperature creep resistance can be improved by growing the matrix microstructure, but the beta grain growth invites a decrease in the high-temperature fatigue property and ductility. Therefore, the optimal particle volume should be determined from the point of view of compatibility of the sufficient high-temperature creep resistance, high-temperature fatigue property, and ductility of the exhaust valve. Taking into account all these properties and productivity, the optimal amount of TiB particle was determined to be 5 vol.%
Table II compares the mechanical properties of the developed TiB- Ti MMC and the 21-4N steel at room and elevated temperatures.
ENGINE VALVE PERFORMANCE
Figure 7 shows the developed valves. The intake valve was also made from a titanium-based alloy manufactured via the same cost- effective process as that for the exhaust valve, but it used the conventional Ti-6Al-4V alloy since it does not require as much heat. The developed P/M process resulted in a cost reduction, enabling the application of lightweight titanium valves.
A new engine in which the developed valves were installed, when compared with the conventional steel-valve engine, had a 40% lighter valve weight and 16% lighter valve spring weight. As a result, the maximum revolutions increased by 700 rpm, and the noise in the high- revolution range decreased by 30%. Moreover, the reduction of friction reduced camshaft driving torque by 20%, and high performance and low fuel consumption were achieved.
CONCLUSION
Figure 8 shows examples of prototype DR-Ti MMC components manufactured by the be process. The new material presented in this report has the potential to fundamentally overturn the concept of cost/performance of conventional titanium alloys, and the author believes it may represent a breakthrough in the application of titanium to mass-produced automobiles.
More than 500,000 P/M Ti-MMC valves have been put into the market since 1998; however, production expansion has been delayed. The main reason for the stagnation is cost. Although this valve is cheaper than others made of titanium, it is still about twice as expensive as the current steel valve. Titanium automobile components will never find practical application unless they can compete in cost/ performance with steel components. The greatest production cost reduction would result by eliminating post-sinter processing such as hot-extruding, hot-forging, heat-treating, and machining. The post- sinter processing cost exceeds 60% of the total cost for the products. The author believes that development of a true dense precision forming technology by means of metal-die compaction with pressure-less sintering is the ultimate goal for generalizing the DR- Ti MMC automobile components.9,10
References
1. F.H. Froes, D. Eylon, and H. Bomberger, editors, Titanium Technology: Present Status and Future Trends (Dayton, OH: TDA, 1985).
2. T. Yamaguchi, T. Furuta, and T. Saito, "Development of P/M Titanium Engine Valve," SAE Technical Paper 01-0905 (Warrendale, PA: SAE, 2000).
3. T. Saito and T. Furuta, "Titanium Alloy Matrix Composite by Reaction Sintering," Current Advances in Materials and Processes (Tokyo: Iron & Steel Institute of Japan, 1991), p. 1740.
4. T. Saito et al., "A New Low Cost MMC of TiB Particle Dispersed in Titanium Alloy," Proc. Conf. 1993 Powder Met. World Congress, ed. Y. Bando and L. Kosuge (Kyoto, Japan: JPMA-JSPM, 1993), pp. 642- 645.
5. T. Saito, T. Furuta, and T. Yamaguchi, "Development of Low- Cost Titanium Matrix Composite," Recent Advances in Titanium Metal Matrix Composites, ed. F.H. Froes and J. Storer (Warrendale, PA: TMS, 1995), pp. 33-44.
6. T. Saito, "A Low-Cost P/M Titanium Matrix Composite for Automobile Use, "Advanced Performance Materials, 2 (1995), pp. 121- 144.
7. T. Saito, H. Takamiya, and T. Furuta, "Thermomechanical Properties of P/M beta Titanium Metal Matrix Composite," Material Science and Engineering, A243 (1998), pp. 273-278.
8. K. Kawabata, E. Sato, and K. Kuribayashi, "Composite Weakening and Strengthening of Ti/TiB(w) Composites During Steady State Creep at High Temperature in the Beta Matrix Region," Scripta Materialia, 50 (2004), pp. 523-527.
9. T. Saito, "New Titanium Products via Powder Metallurgy Process," Proc. Cont. Wtb World Conference on Titanium, ed. G. Lutjering (Hamburg, Germany: DGM, 2003), in press.
10. H. Takamiya, M. Kondoh, and T. Saito, "Ultra-High Pressure Warm Compaction for P/M Titanium Components," Cost-Affordable Titanium, ed. FH. Froes, M. Ashraf, and D. Fray (Warrendale, PA: TMS, 2004), pp. 185-192.
Takashi Saito is director of the Materials Department at Toyota Central Research and Development Laboratories in Aichi, Japan.
For more information, contact Takashi Saito, Toyota Central Research and Development Laboratories, Materials Department, 41-1 Yokomichi Nagakute Aichi, 480-1192 Japan; 011-81-561-63-3090; fax 011-81-561-63-5441; e-mail saito@mosk.tytlabs.co.jp.
Copyright Minerals, Metals & Materials Society May 2004
