断口表面粗糙度的定量分析

QUANTITATIVE ANALYSIS ON SURFACE ROUGHNESS OF FRACTURE

利用互成１２０°角均匀垂直切割断口表面的方法对典型的低温冲击断口进行了定量测量．对于曲折程度不同的断口表面应选取不同的放大倍数，放大倍数选取适当，测得的断口表面粗糙度Ｒ_Ｓ才与材料的冲击值相对应．利用此种测量方法，通过Ｒ_Ｓ与Ｒ_Ｌ的系数转换，还可较好地测定断口表面面分数维Ｄ_Ｓ．把该方法测得的Ｒ_Ｓ值与用Ｗｒｉｇｈｔ和Ｓｏｕｄａｎｉ导出的两种Ｒ_Ｓ－Ｒ_Ｌ关系式算出的Ｒ_Ｓ值相比较，进一步证实了该方法的有效性。此外还提出了一种利用断口镀层厚度来估计Ｒ_Ｓ的方法．

The quantitative measurements of the typical low-temperature impact fracture surfaces were made by the method for such an even fracture surface vertically cutting apart into mutual 120°angle. The magnification is found to be dependent significantly on the value of measurement. The magnification selected is quite different upon the zigzaging.R_S, of fracture surface. The corresponding impact value of material may match the roughness.R_S, of the fracture surface measured only with a magnification properly selected. Using the present measuring method and based on the convension of coefficients R_S and R_L, a fair measurement of the fractal dimension, D_S, for fracture surface may be also obtained. The comparison of R_S value, measured by this method, with the derived ones from the relation between R_S vs R_L, deduced by Wright and Soudani, may further confirm the effectiveness of this method. Moreover, a method may be proposed to estimate R_S by the plating thickness of the fracture surface.