Zr基大块非晶合金的微区变形及力学性能

Deformation and mechanical properties of Zr-based bulk metallic glasses under nanoindenter

利用纳米压痕仪、扫描电镜等研究了Zr基大块非晶合金在纳米压痕条件下的变形及力学性能。Zr基大块非晶合金在纳米压头作用下以弹性塑性方式变形 ,载荷—位移曲线及压痕周边多重剪切带 (堆起或波纹状 )的特征证明了塑性变形的存在。冷却速度、第二相及退火等因素影响非晶合金的压痕硬度HV和弹性模量E ,冷却速度小的试样或部位 (如试样中心 )的HV ,E值略高 ;离第二相 (W丝 )越近 ,HV ,E值越高 ;退火处理提高非晶的HV ,E值 ,同时退火与第二相还明显改变压痕周边的变形状态及塑性变形量的大小 ,退火显著减小塑性变形量 ,使压痕周边凹陷 ,而第二相使压痕堆起消失。对塑性变形机理进行了初步分析。

Deformation and mechanical properties of Zr-based bulk metallic glasses (BMGs) under nanoindenter and their affecting factors were studied by means of nanoindentation instrument and scanning electron microscope (SEM). The results indicate that Zr-based BMGs deform in an elastic-plastic mode under a nanoindenter. Load—displacement curve, multiple shear bands and ripple shape around a nanoindenter confirm the existence of a amount of plastic deformation. For pure quenched Zr-based BMGs, the larger the size of samples or the nearer the location away from the surface of a same sample, the smaller the values of microhardness and elastic modulus; annealing and tungsten fiber addition both enhance the values of HV and E, and significantly change the morphology around a nanoindenter and the amount of plastic deformation. The mechanism of plastic deformation is preliminarily analyzed.