论文部分内容阅读
采用有限元法对材料表面改性层和薄膜材料在显微压入过程中的力学行为进行了计算机模拟。从所得的载荷与压入深度的关系曲线、压痕周围应力、应变场的大小和形状分布曲线等为依据，对在超显微硬度测试中基底材料及界面层的影响进行了详细的讨论，并得出：为排除基底材料的影响，通常规定压入深度（Ｄ）不得超过膜厚（ｔ）的１０～２０％的规则并不适用于所有薄膜系统。测试时，允许的Ｄ／ｔ的临界比值将随薄膜系统不同而异。对软膜硬基底系统而言，由于压头下的塑性应变区更多的是沿膜层的横向扩展，故Ｄｃ／ｔ允许大于上述规定值，而对硬膜软基底系统而言，则由于压头下的塑性应变区很容易扩展到基底材料中去，其Ｄｃ／ｔ值将小于上述规定值。
The mechanical behavior of the surface modification layer and the thin film material during the micro-press-in process was simulated by finite element method. Based on the relationship between the load and the depth of indentation, the stress and strain field around the indentation and the shape distribution curve, the effects of the substrate material and interface layer in the ultra-microhardness test are discussed in detail. And concluded that to rule out the effects of the base material, rules that normally provide a depth of intrusion (D) that does not exceed 10-20% of film thickness (t) are not applicable to all film systems. When testing, the critical D / t ratio allowed will vary with the membrane system. For soft film hard substrate systems, Dc / t is allowed to exceed the above specified value because the plastic strain zone under the indenter is more along the film’s lateral extent, whereas for dura soft substrate systems, The plastic strain zone under the ram can easily be extended into the base material and the Dc / t value will be less than the above specified value.