Al含量对空心阴极等离子烧结Ti/Ni等原子比TiNiAl合金组织和力学性能的影响

 采用空心阴极等离子烧结工艺制备了Ti/Ni等原子比的Ti_50-x/2Ni_50-x/2Al_x(x=0,3,6,9)合金,研究了Al含量对合金微观组织以及力学性能的影响。结果表明:未添加铝的合金微观组织主要由NiTi基体、强化相Ti₂Ni、Ni₃Ti及孔隙组成;随着Al含量的提高,合金中Ti₂Ni(Al)数量不断增多,孔隙数量和孔径不断增加,Ni₃Ti(Al)数量不断减少,在Ti_45.5Ni_45.5Al₉中还生成了少量Ni₂TiAl相;合金的抗弯强度随Al含量的提高而增加,并在Al含量为6%时达到最大值296.3 MPa;合金的硬度随铝含量的提高而增加,Ti_45.5Ni_45.5Al₉的硬度值为295.6 HV。

Effect of Al Content on Microstructure and Mechanical Properties of Hollow Cathode Plasma Sintering TiNiAl Alloys with Equal Ti/Ni Atom Ratio

Ti_50-x/2Ni_50-x/2Al_x(x=0, 3, 6, 9) intermetallic compounds with equal Ti/Ni atom ratio are fabricated through hollow cathode plasma sintering process, and the effect of Al content on the microstructure and mechanical properties of the alloys is investigated. The results show that the microstructure of an alloy without Al consists chiefly of the NiTi matrix, some strengthening phase Ti₂Ni, Ni₃Ti and some pores; with the addition and increase of the Al content, the amount of Ti₂Ni(Al) increases while that of Ni₃Ti(Al) decreases and a small amount of Ni₂TiAl is formed in Ti_45.5Ni_45.5Al₉, while the amount of pores and their sizes increase. The flexural strength of the alloys increases with increasing Al content and reaches the maximum of 296.3 MPa when Al content is 6%, and then it starts to decrease as Al content further increases. The hardness of the alloys increases with increasing Al content and the hardness of Ti_45.5Ni_45.5Al₉ reaches 295.6 HV.