晶体取向对镍基单晶高温合金纳米压痕行为的影响

Effect of crystallographic orientation on nano-indentation behaviors of Nickel based single crystal super alloys

摘要:

为了研究晶体取向对镍基单晶高温合金纳米压痕行为的影响，采用带原子力显微镜的Berkovich压头对[001], [011]和[111]取向的镍基单晶高温合金开展了纳米压痕试验。试验结果显示晶体取向对压痕载荷-深度曲线、硬度和弹性模量有显著影响。晶体取向会影响γ^"强化相形状和体积分数，进而会影响其力学性能。采用晶体塑性理论对三种典型晶体取向下的纳米压痕响应和分解切应力分布开展有限元模拟，模拟结果与试验结果符合得较好。

Abstract:

In order to investigate the effect of crystallographic orientation on the nano-indentation behaviors of single crystal super alloys, the nano-indentation experiments with a Berkovich indenter in an atomic force microscope were carried out on [001], [011] and [111] oriented Nickel based single crystal super alloys. Experimental results showed that the indentation load-depth curve, hardness and elastic modulus were remarkably influenced by crystallographic orientation. It is found that the shape and volume fraction of γ^" strengthening phase is dependent on crystallographic orientation, which will influence the mechanical properties. The nano-indentation experiments performed on three typical crystallographic orientations were simulated by using crystal plasticity theory to investigate the indentation responses and the resolved shear stress induced by indentation, and the simulation results showed a good agreement with the experiment results.