评价强界面涂层界面结合能力的横截面压入法

Cross-sectional Indentation Method to Evaluate Strong Interface Adhesive Strength

为了解强界面脆性涂层/硬性金属基体涂层结构横截面压入时的涂层剥落特点,以电镀铬层/硬性金属基体为研究模型,在原位观察系统下进行横截面压入试验,其结果表明:铬层断裂和剥落与载荷-位移曲线上出现的3个载荷下降点相对应,首先是在铬层横截面上形成一条与压头轴线平行的中间裂纹;随后又出现了以第1条裂纹为对称轴的2条斜裂纹;随着3条裂纹的稳态扩展和汇合,形成了与周围铬层相隔离、仅靠基体支撑的2块1/4圆形局部“孤岛”铬层;最后“孤岛”铬层沿界面剥落。以此“孤岛”剥落为力学计算模型,提出定量评价强界面脆性涂层/硬性金属基体的界面结合能力的横截面压入法,该方法利用载荷-位移曲线计算“孤岛”剥落所需要的总能量,测量界面剥落面积,并计算两者的比值,给出临界界面能量释放率,以此数据作为评价界面结合能力的指标,并给出了应用举例。

In order to understand the chromium coatings spallation characteristic when the cross-sectional indentation experiment on strongly interracial brittle coating/hard metal substrate, the chromium-plating on hard metal substrate is used as studied model, the cross-sectional indentation experiment is carried out with the help of in situ observational system. The result shows that the coatings crack and spallation corresponds to three load dropping points of load-displacement, firstly, a middle crack corresponding to the indenter axis forms on the chromium coatings cross-section, then, two symmetric inclined cracks to middle crack form, with the propagation and intersection of above three cracks, two chromium coatings ＂ island＂ of one fourth circle shape form, which separate from other Cr coatings and are supported only by the substrate, in the final, ＂ island＂ spalls along the interface. Based on the mechanical model of the ＂ island＂ spallation, the cross-sectional indentation method to evaluate strong interfacial adhesion is presented. In the method, the interfacial spallation energy is calculated through the load-displacement curve and spallation area is measured, the critical interface energy release rate is given by the above two values. As applied example, the adhesive ability of the experimental sample is measured.