The effective elastic moduli （EEM） of A356/TiB2 composites formed by gravity casting and adjusted pressure casting （APC） were measured and compared. The results show that the EEM of A356/TiB2 composites are improv...The effective elastic moduli （EEM） of A356/TiB2 composites formed by gravity casting and adjusted pressure casting （APC） were measured and compared. The results show that the EEM of A356/TiB2 composites are improved obviously by TiB2 particles and affected by forming methods. The EEM of the specimens formed by APC are higher than those in the gravity casting case. For 9.5%A356/TiB2（volume fraction）, the EEM of the specimens formed by APC reaches 93GPa, which is 9GPa higher than those in the gravity casting case. An analytic model is established to explain the mechanics of the EEM of composites reinforced with TiB2 particles.展开更多
TiB2/C cathode composites with various contents of TiB2 were prepared and their characterizations were observed and compared. The expansion of samples due to sodium and bath penetration was tested with a modified labo...TiB2/C cathode composites with various contents of TiB2 were prepared and their characterizations were observed and compared. The expansion of samples due to sodium and bath penetration was tested with a modified laboratory Rapoport apparatus and the appearances of the cut sections of specimens after electrolysis were studied. The results show that the mass of TiB2/C cathode composites with mass fraction of TiB2 less than 70% appreciably increases, but that of the composites with mass fraction of TiB2 more than 70% decreases slightly after being baked. The resistance to sodium and bath penetration of TiB2/C cathode composites increases with the increase of TiB2 content, especially in the composites with high TiB2 content. TiB2/C cathode composites have high resistance to the penetration of sodium and bath as well as good wettability by molten aluminum, and keep integrality and have little change of appearance after electrolysis, which indicates that TiB2/C cathode composites can be used as inert wettable cathode for aluminum electrolysis.展开更多
The partially stabilized ZrO2 (PSZ) particles were introduced into TiB2 ceramics to improve its density and mechanical properties. The results show that the addition of PSZ is very effective not only in bettering the ...The partially stabilized ZrO2 (PSZ) particles were introduced into TiB2 ceramics to improve its density and mechanical properties. The results show that the addition of PSZ is very effective not only in bettering the sinterability but also in enhancing the flexural strength and fracture toughness of TiB2.展开更多
In order to develop a high damping aluminum alloy with strength, in-situ A356/TiB2 composite fabricated with an exothermic reaction process via K2TiF4 and KBF4 salts were studied. The damping behavior of materials ove...In order to develop a high damping aluminum alloy with strength, in-situ A356/TiB2 composite fabricated with an exothermic reaction process via K2TiF4 and KBF4 salts were studied. The damping behavior of materials over a temperature range of 30300℃ was investigated using a dynamic mechanical thermal analyzer. Experimental findings indicate that damping capacity of A356/TiB2 composite is higher than that of A356 base alloy. Damping capacity of materials increases with increasing temperature while decreases with increasing frequency. Interestingly, the improvement of both damping capacity and tensile strength is observed simultaneously.展开更多
In situ A356-x%PVF （particle volume fraction） ZrB2 （ x=1, 3, 5） composites were prepared via magneto-chemistry in situ reaction and the dry sliding wear properties of the composites were investigated. The experime...In situ A356-x%PVF （particle volume fraction） ZrB2 （ x=1, 3, 5） composites were prepared via magneto-chemistry in situ reaction and the dry sliding wear properties of the composites were investigated. The experimental results show that ZrB2 reinforcement particle is obtained and its morphology mainly present in spherical and regular hexagon. Wear test results show that the values of wear weight loss of the composites decrease with the increase of value under a given sliding time and a certain load of 60 N. Especially, when x=5, the weight loss of the as-prepared composite is 43.1 mg, which is only 36.4% to that ofA356 alloy, 118 rag. The wear mechanism is changed from adhesion wear to adhesion wear and abrasive wear and then to abrasive wear with the increase of x value.展开更多
TiB_(2p)/Cu composites with high reinforcement content(φ_(p)=50%,58%and 65%)for electronic packaging applications were fabricated by squeeze casting technology.The microstructures and thermo-physical properties of th...TiB_(2p)/Cu composites with high reinforcement content(φ_(p)=50%,58%and 65%)for electronic packaging applications were fabricated by squeeze casting technology.The microstructures and thermo-physical properties of the TiB_(2p)/Cu composites were investigated.The results show that TiB2 particles are homogeneous and distribute uniformly,and the TiB2-Cu interfaces are clean and free-from interfacial reaction products and amorphous layers,the densifications of the TiB_(2p)/Cu composites are higher than 98.2%. The mean linear coefficients of thermal expansion at 20-100℃for TiB_(2p)/Cu composites range from 8.3×10^(-6)to 10.8×10^(-6)/K and decrease with increasing volume fraction of TiB2.The experimental coefficients of thermal expansion agree well with the predicted values based on Turner’s model.The thermal conductivities of TiB_(2p)/Cu composites range from 167.3 to 215.4 W/(m·K),decreasing with increasing volume fraction TiB2.展开更多
The microstructure and mechanical properties of TiB_2 /B_4C composites have been investi- gated.It was found that both the strength and hardness for TiB_2 greatly increase with the ad- dition of 20 to 30 wt-% B_4C,and...The microstructure and mechanical properties of TiB_2 /B_4C composites have been investi- gated.It was found that both the strength and hardness for TiB_2 greatly increase with the ad- dition of 20 to 30 wt-% B_4C,and the fracture toughness K_(IC) value remaines on the original high level.The flexure strength,Vicker's hardness and fracture toughness are 782 MPa,26.2 GPa and 7.2 MPam^(1/2),respectively,for the TiB_2-30 wt-% B_4C composite,compared to 450 MPa,21 GPa and 7.0 MPam^(1/2) for monolithic TiB_2.The toughening and strengthening mechanisms,have also been discussed.展开更多
Ni-50at.%A1 matrix composites containing 0 to 20v.% TiB2 particles have been successfully fabricated by HPES technique. The results show that the Vickers hardness at room temperature and the compressive yield strength...Ni-50at.%A1 matrix composites containing 0 to 20v.% TiB2 particles have been successfully fabricated by HPES technique. The results show that the Vickers hardness at room temperature and the compressive yield strength from room temperature to 1000℃ of the composites increase with increasing volume fraction of the strengthening phase. Especially, the yield strength of NiAl-20TiB2 was approximately twice as high as that of unreinforced NiAl. The ductility of the composites at room temperature is also superior to the monolithic NiAl.展开更多
文摘The effective elastic moduli （EEM） of A356/TiB2 composites formed by gravity casting and adjusted pressure casting （APC） were measured and compared. The results show that the EEM of A356/TiB2 composites are improved obviously by TiB2 particles and affected by forming methods. The EEM of the specimens formed by APC are higher than those in the gravity casting case. For 9.5%A356/TiB2（volume fraction）, the EEM of the specimens formed by APC reaches 93GPa, which is 9GPa higher than those in the gravity casting case. An analytic model is established to explain the mechanics of the EEM of composites reinforced with TiB2 particles.
文摘TiB2/C cathode composites with various contents of TiB2 were prepared and their characterizations were observed and compared. The expansion of samples due to sodium and bath penetration was tested with a modified laboratory Rapoport apparatus and the appearances of the cut sections of specimens after electrolysis were studied. The results show that the mass of TiB2/C cathode composites with mass fraction of TiB2 less than 70% appreciably increases, but that of the composites with mass fraction of TiB2 more than 70% decreases slightly after being baked. The resistance to sodium and bath penetration of TiB2/C cathode composites increases with the increase of TiB2 content, especially in the composites with high TiB2 content. TiB2/C cathode composites have high resistance to the penetration of sodium and bath as well as good wettability by molten aluminum, and keep integrality and have little change of appearance after electrolysis, which indicates that TiB2/C cathode composites can be used as inert wettable cathode for aluminum electrolysis.
文摘The partially stabilized ZrO2 (PSZ) particles were introduced into TiB2 ceramics to improve its density and mechanical properties. The results show that the addition of PSZ is very effective not only in bettering the sinterability but also in enhancing the flexural strength and fracture toughness of TiB2.
文摘In order to develop a high damping aluminum alloy with strength, in-situ A356/TiB2 composite fabricated with an exothermic reaction process via K2TiF4 and KBF4 salts were studied. The damping behavior of materials over a temperature range of 30300℃ was investigated using a dynamic mechanical thermal analyzer. Experimental findings indicate that damping capacity of A356/TiB2 composite is higher than that of A356 base alloy. Damping capacity of materials increases with increasing temperature while decreases with increasing frequency. Interestingly, the improvement of both damping capacity and tensile strength is observed simultaneously.
基金Funded by the National Natural Science Foundation of China(No.50971066)the Jiangsu Provincial'333'Project of training the Highlevel Talents Foundation(No.2008-46)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘In situ A356-x%PVF （particle volume fraction） ZrB2 （ x=1, 3, 5） composites were prepared via magneto-chemistry in situ reaction and the dry sliding wear properties of the composites were investigated. The experimental results show that ZrB2 reinforcement particle is obtained and its morphology mainly present in spherical and regular hexagon. Wear test results show that the values of wear weight loss of the composites decrease with the increase of value under a given sliding time and a certain load of 60 N. Especially, when x=5, the weight loss of the as-prepared composite is 43.1 mg, which is only 36.4% to that ofA356 alloy, 118 rag. The wear mechanism is changed from adhesion wear to adhesion wear and abrasive wear and then to abrasive wear with the increase of x value.
基金Project(20080430895)supported by China Postdoctoral Science FoundationProject(2008RFQXG045)supported by the Special Fund of Technological Innovation of Harbin,China。
文摘TiB_(2p)/Cu composites with high reinforcement content(φ_(p)=50%,58%and 65%)for electronic packaging applications were fabricated by squeeze casting technology.The microstructures and thermo-physical properties of the TiB_(2p)/Cu composites were investigated.The results show that TiB2 particles are homogeneous and distribute uniformly,and the TiB2-Cu interfaces are clean and free-from interfacial reaction products and amorphous layers,the densifications of the TiB_(2p)/Cu composites are higher than 98.2%. The mean linear coefficients of thermal expansion at 20-100℃for TiB_(2p)/Cu composites range from 8.3×10^(-6)to 10.8×10^(-6)/K and decrease with increasing volume fraction of TiB2.The experimental coefficients of thermal expansion agree well with the predicted values based on Turner’s model.The thermal conductivities of TiB_(2p)/Cu composites range from 167.3 to 215.4 W/(m·K),decreasing with increasing volume fraction TiB2.
文摘The microstructure and mechanical properties of TiB_2 /B_4C composites have been investi- gated.It was found that both the strength and hardness for TiB_2 greatly increase with the ad- dition of 20 to 30 wt-% B_4C,and the fracture toughness K_(IC) value remaines on the original high level.The flexure strength,Vicker's hardness and fracture toughness are 782 MPa,26.2 GPa and 7.2 MPam^(1/2),respectively,for the TiB_2-30 wt-% B_4C composite,compared to 450 MPa,21 GPa and 7.0 MPam^(1/2) for monolithic TiB_2.The toughening and strengthening mechanisms,have also been discussed.
文摘Ni-50at.%A1 matrix composites containing 0 to 20v.% TiB2 particles have been successfully fabricated by HPES technique. The results show that the Vickers hardness at room temperature and the compressive yield strength from room temperature to 1000℃ of the composites increase with increasing volume fraction of the strengthening phase. Especially, the yield strength of NiAl-20TiB2 was approximately twice as high as that of unreinforced NiAl. The ductility of the composites at room temperature is also superior to the monolithic NiAl.
