The influence of in-situ synthesized TiC nanoparticles on age-hardening behavior of Al–Cu alloys was investigated in Al–4.5 Cu–1.5 TiC alloy. It was found that TiC nanoparticles decrease the peak-age time effective...The influence of in-situ synthesized TiC nanoparticles on age-hardening behavior of Al–Cu alloys was investigated in Al–4.5 Cu–1.5 TiC alloy. It was found that TiC nanoparticles decrease the peak-age time effectively, from about 20 h for Al–4.5 Cu alloy decreasing to about 12 h for the Al–4.5 Cu–1.5 TiC. Mechanical property test shows that the age-hardening effect has been improved by the TiC nanoparticles. The increment of yield strength before and after aging is about 84 MPa for Al–4.5 Cu, while, it reaches to about113 MPa for the Al–4.5 Cu–1.5 TiC. After aging heat treatment, precipitates have been observed both in matrix and around TiC nanoparticles. Due to the difference of coefficient of thermal expansion between TiC and Al, high density dislocations in the Al–4.5 Cu–1.5 TiC were generated during water quenching after solution. Dislocations play a role of diffusion path for Cu atoms during aging, which reduces the peak-age time. Alpha-Al lattice distortion resulted from lattice mismatch of TiC/Al interface induces the precipitation of θ' phase around TiC nanoparticles, which increases the number density of θ' and improves the age-hardening effect. This finding is supposed to be also applicable to alloy systems of Al–Cu–Mg,Al–Cu–Mg–Li, Al–Cu–Mg–Ag, etc.展开更多
TiC_x contained Al-Ti-C is a kind of grain refiner for Al alloys. In this work, the influence of C/Ti stoichiometry, i.e. the x value in TiC_x on grain refinement efficiency was investigated. TiC_x particles have been...TiC_x contained Al-Ti-C is a kind of grain refiner for Al alloys. In this work, the influence of C/Ti stoichiometry, i.e. the x value in TiC_x on grain refinement efficiency was investigated. TiC_x particles have been obtained in five Al-5Ti-m C（m = 0.1, 0.5, 0.8, 1, 1.25） master alloys and the x values were measured to be0.72, 0.75, 0.79, 0.81 and 0.8, respectively. It was found that the refinement performance of the master alloys had a close relationship with the x value of TiC_x . The Al-5Ti-m C alloy with lower-x TiC_x shows better refinement efficiency and anti-fading capability. It is supposed that TiC_x particles with lower x are more preferred to release Ti atoms during nucleating process and have a better Ti-absorbing capability.This contributes to the Ti-rich zone formation at TiC_x /melt interface, thus enhancing the refinement and anti-fading capability.展开更多
基金financially supported by the Key Program of the National Natural Science Foundation of China (No. 51731007)the National Natural Science Foundation of China (No. 51501092)
文摘The influence of in-situ synthesized TiC nanoparticles on age-hardening behavior of Al–Cu alloys was investigated in Al–4.5 Cu–1.5 TiC alloy. It was found that TiC nanoparticles decrease the peak-age time effectively, from about 20 h for Al–4.5 Cu alloy decreasing to about 12 h for the Al–4.5 Cu–1.5 TiC. Mechanical property test shows that the age-hardening effect has been improved by the TiC nanoparticles. The increment of yield strength before and after aging is about 84 MPa for Al–4.5 Cu, while, it reaches to about113 MPa for the Al–4.5 Cu–1.5 TiC. After aging heat treatment, precipitates have been observed both in matrix and around TiC nanoparticles. Due to the difference of coefficient of thermal expansion between TiC and Al, high density dislocations in the Al–4.5 Cu–1.5 TiC were generated during water quenching after solution. Dislocations play a role of diffusion path for Cu atoms during aging, which reduces the peak-age time. Alpha-Al lattice distortion resulted from lattice mismatch of TiC/Al interface induces the precipitation of θ' phase around TiC nanoparticles, which increases the number density of θ' and improves the age-hardening effect. This finding is supposed to be also applicable to alloy systems of Al–Cu–Mg,Al–Cu–Mg–Li, Al–Cu–Mg–Ag, etc.
基金supported by a grant from the National Natural Science Fund of China (No. 51501092)the National Basic Research Program of China (No. 2012CB825702)
文摘TiC_x contained Al-Ti-C is a kind of grain refiner for Al alloys. In this work, the influence of C/Ti stoichiometry, i.e. the x value in TiC_x on grain refinement efficiency was investigated. TiC_x particles have been obtained in five Al-5Ti-m C（m = 0.1, 0.5, 0.8, 1, 1.25） master alloys and the x values were measured to be0.72, 0.75, 0.79, 0.81 and 0.8, respectively. It was found that the refinement performance of the master alloys had a close relationship with the x value of TiC_x . The Al-5Ti-m C alloy with lower-x TiC_x shows better refinement efficiency and anti-fading capability. It is supposed that TiC_x particles with lower x are more preferred to release Ti atoms during nucleating process and have a better Ti-absorbing capability.This contributes to the Ti-rich zone formation at TiC_x /melt interface, thus enhancing the refinement and anti-fading capability.
