基于微纳米压入法的高熵合金柏氏矢量研究

Study on Burgers Vector of High-Entropy Alloy Based on Nano-Indentation Method

采用微纳米压入法对CoCrFeNiMn高熵合金进行多种应变率下的压入测试研究,实验获得了材料硬度与压深之间的关系并通过计算分析得到了其不同工况下的柏氏矢量值,探究了压入深度和应变率对柏氏矢量的影响.实验结果表明,所测材料柏氏矢量值在一定范围内呈现出一定的波动性,随着压深的增大,柏氏矢量表现出尺寸效应,即柏氏矢量随压深呈增加趋势;并且在同等压深下,柏氏矢量存在率效应,随着应变率的增加,柏氏矢量值先减小后增加,柏氏矢量从滑移主导向原子失配主导的转变是其率效应转变的主要原因.

The indentation tests of CoCrFeNiMn high-entropy alloy at various strain rates were carried out by nano-indentation method.The relationship between the hardness and the indentation depth was obtained,And the Burgers vector magnitudes under different working conditions were analyzed and calculated.The influences of indentation depth and strain rate on the Burgers vector were investigated.The experimental results show that the measured values of the Burgers vector exhibit fluctuation in a certain range.With the increase of the indentation depth,the Burgers vector exhibits size effect,i.e.,a tendency of increase with the indentation depth.While at the same depth,the Burgers vector exhibits rate effect,As the strain rate increases,the Burgers vector decreases first and then increases,which can be mainly attributed to the change of Burgers vector mechanism from slip-dominated to atom-misfit-dominated.