纳米压痕法测量Ti6Al4V钛合金室温蠕变应力指数

Nanoindentation Measurement of Creep Stress Exponent of Ti6Al4V Alloy at Room Temperature

主要通过恒加载速率纳米压痕法的保载阶段测量了Ti6Al4V钛合金在室温下的蠕变应力指数n。通过给金刚石Berkovich压头施加不同的加载速率使其达到不同的最大载荷,观察加载速率和最大载荷对实验结果的影响。在最大载荷下,给压头保载5 min,通过保载过程中材料的压痕应变率和硬度之间的关系得到了该材料在常温下的蠕变应力指数n。结果表明,在特定范围内加载速率和最大载荷的变化对实验结果的影响微乎其微,可以忽略不计。最终测得Ti6Al4V钛合金在室温下蠕变应力指数的分布范围为7.0513-7.216。

This paper presents a method for measuring the creep stress exponent of Ti6Al4V alloy at room temperature based on the dwelling period of constant loading rate nanoindentation.As to find out the effect of the loading rate and the maximum load on the experiment result,the diamond Berkovich indenter was loaded to different maximum loads with different loading rates,then the maximum load was held as a constant for 5 min,and the stress exponent of the material at room temperature was discovered based on the relationship between the indentation strain rate and the hardness during the holding period.Results show that the effects of the loading rate and the maximum load are too small to affect the result so that they can be ignored,and the creep stress exponent of Ti6Al4V at room temperature got from the experiment is between 7.0513~7.216.