Ti6Al4V合金的纳米硬度载荷依赖性实验研究

Experimental investigation of Ti6Al4V alloy nanohardness load dependence

采用原位纳米测试系统对氮离子注入前后的Ti6Al4V合金试样进行纳米压痕实验,研究材料纳米硬度的载荷相关性和尺寸效应,及其在纳米尺度下材料的塑性变形过程。结果表明:纳米硬度具有明显的载荷相关性,在临界载荷Fc以下,随着载荷的增加纳米硬度呈线性增加;在临界载荷Fc以上,随着载荷的增加纳米硬度呈非线性减小,并稳定在一个值上。此外,纳米硬度随着压入深度的增加而减小,并且Ti6Al4V合金的纳米硬度极限载荷FH和稳定纳米硬度Hs分别为550μN和5.6GPa,而经过氮离子注入后的Ti6Al4V合金的纳米硬度极限载荷FH和稳定纳米硬度Hs分别提高到700μN和6.7 GPa。

Nanoindentation tests on Ti6Al4V alloys and nitrogen implanted Ti6Al4V alloys using an in situ nano-mechanical testing system were used to analyze the load dependence and size effect of the nanohardness and the plastic deformation. The results show that the nanohardness of the Ti6Al4V alloy increases linearly with increasing loads less than the critical load and then decreases to a steady value with increasing loads above the critical load. The nanohardness decreases with increasing contact depth, with a critical nanohardness load of 550 μN and a Ti6Al4V alloy nanohardness of 5.6 GPa. The critical load and steady nanohardness are increased to 700 μN and 6.7 GPa in the Ti6Al4V alloy implanted with nitrogen.