元素添加方式对Ti-6Al-3Nb-2Zr-1Mo合金性能的影响

Influence of Element Addition Ways on the Performance of Ti-6Al-3Nb-2Zr-1Mo Alloy

摘要:

通过研究元素添加方式对粉末冶金Ti-6Al-3Nb-2Zr-1Mo(Ti80)合金微观组织和力学性能的影响，探索了提高粉末冶金Ti80合金材料性能的途径和方法。结果表明：要得到相对密度大于97%的粉末冶金烧结坯，Al必须以NbAl、ZrAl、MoAl、MoAlTi等中间合金方式进行添加；Nb、Zr可以单质或中间合金方式添加；Mo需要以MoAl或MoAlTi中间合金方式添加。Ti不能完全以TiH2的方式添加；当Ti以纯Ti粉方式添加时，拉伸断口没有裂纹产生；当Ti以TiH2方式添加时，断口有显著的裂纹产生；H是裂纹产生的主要原因。当元素以合适的方式添加时，Ti80合金烧结件的性能可达到：σb=890~1020 MPa，σ0.1=755~875 MPa，σ0.2=785~895 MPa，δ5=5.5%~9.0%，ψ=11%~20%，与锻态性能相比，强度性能有显著提高，而塑性降低。

Abstract:

The influence of element addition ways on the microstructure and the performance of P/M Ti-6Al-3Nb-2Zr-1Mo alloy (Ti80) was investigated in order to improve the processing properties. The results indicate that Al must be added by NbAl, ZrAl, MoAl or MoAlTi pre-alloy to obtain the relative density above 97%; Nb and Zr can be added by elementary substance or pre-alloy; Mo should be added by MoAl or MoTiAl pre-alloy. Ti can not completely added by TiH2 powder. The tensile fracture of P/M Ti80 alloy exhibits outstretch rupture and has no crack when Ti is added by Ti powder while the tensile fracture shows brittle rupture and has distinct cracks when Ti is added by TiH2 powder. Hydrogen is the main reason causing cracks of the alloy. Adopting appropriate element addition ways, good performance of the P/M Ti80 alloy can be obtained, such as σb=890-1020 MPa, σ0.1=755-875 MPa, σ0.2=785-895 MPa, δ5=5.5%-9.0%, and ψ=11%-20%. Compared with the forged alloy, the sintered alloy has much higher intensity and lower plasticity.