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 Behavior of Nickel Based Single Crystal Super Alloys

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′强化相的形状和体积分数,进而会影响其力学性能。采用晶体塑性理论对3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。

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