基于纳米划痕的单晶锗脆塑转变实验研究

Experimental Research on Brittle-Ductile Transition of Single Crystal Germanium Based on Nano-Scratch

为了考察单晶锗的脆塑转变,利用纳米压痕仪分别对单晶锗(100)、(110)和(111)晶面进行纳米划痕实验,并利用原子力显微镜和扫描电子显微镜对划痕形貌进行观察。通过对划痕深度-距离曲线及划痕形貌进行分析,获取各晶面脆塑转变临界载荷和临界深度。结果表明,单晶锗具有强烈的各向异性,(100)、(110)和(111)晶面脆塑转变临界载荷分别为37.6、30.5和32.4mN,临界深度分别为594.7、512.5和536.6nm。(100)晶面因其具有最小硬度、最深脆塑转变深度,在划痕过程中塑性去除最多,脆塑转变最晚,而且随着划痕速度的增加,脆塑转变临界深度和临界载荷也相应增加。最后恒定载荷划痕实验验证了脆塑转变临界载荷和临界深度的正确性。

In order to examine the brittle-ductile transition of single crystal germanium, nano-scratch experiments were conducted on（100）,（110） and（111） crystal planes using nano-indenter, and the scratch morphology was observed by atomic force microscopy and scanning electron microscope. The critical load and critical depth of the brittle-ductile transition of each crystal plane were obtained by analyzing the scratch depth-scratch distance curve and the scratch morphology. The results show that single crystal germanium has strong anisotropy, the critical loads of brittle-ductile transition on the（100）,（110） and（111） crystal planes are 37.6, 30.5 and 32.4 mN, and the critical depths are 594.7, 512.5 and 536.6 nm, respectively. The largest plastic removal and the latest brittle-ductile transition on the（100） crystal plane during the process of nano-scratch are due to its minimum hardness and deepest depth of brittle-ductile transition, and with the increase of scratch speed, the critical depth and critical load of brittle-ductile transition increase. The correctness of the critical load and the critical depth of the brittle-ductile transition is verified through constant load scratch test.