纳米尺度单晶锗各向异性摩擦磨损性能试验研究

利用纳米压痕仪和原子力显微镜,分别对单晶锗Ge(100)、Ge(110)、Ge(111)3种晶向的表面进行纳米尺度下的摩擦磨损试验。在较大载荷的条件下,3种不同晶面取向的单晶锗磨损情况均呈现沟槽形式,沟槽两侧出现明显的碎屑堆积现象。在划痕试验过程中,单晶锗的磨损性能受晶面取向影响较小;单晶锗的摩擦力随着滑动速度的增加而增加。而且,随着滑动速度的增大,晶体表面出现严重的磨损-沟槽损伤,沟槽两侧碎屑堆积的体积也越来越大,沟槽的深度也逐渐增大;单晶锗在较低载荷下,摩擦力基本保持稳定,但随着载荷的增大,单晶锗的摩擦力呈非线性增长,载荷增大一定值时,晶体表面发生明显的由塑性变形向脆性破坏转变的脆塑转变过渡过程,导致单晶锗表面发生脆性剥离,形成沟槽两侧碎屑堆积。

Friction and Wear Experiments on Anisotropic Properties of Single Crystal Germanium in Nanoscale

The friction and wear experiment has been done in the crystal surface of Ge(100), Ge(110) and Ge(111) in nanoscale by nano-indenter and Atomic force Microscope. Under heavy load conditions, the grooves appear in all of the friction of three different single plane orientations, and the debris accumulate obviously on the verge of nick. As shown in the friction experiment, the effect of crystal orientation is slight on the friction performance of single crystal germanium. The friction force of single crystal germanium increases along with the increment of sliding velocity. Whereas, with the increment of sliding velocity, severe friction trench damage occurs in the crystal surface, the volume of accumulated debris on the verge of nick and the depth of groove become bigger. Under low load conditions, the friction is stable basically. But with the increment of load, the friction of crystal germanium is of nonlinear growth, and there is a brittle plastic transition from plastic deformation to brittle failure on the crystal surface, causing the brittle stripping of the surface of single crystal germanium and the debris accumulation on the two sides of the groove when the load increases to a certain value