SiC/Al2O3纳米复合材料压痕周围残余应力的压谱特性研究

提出了用拉曼显微镜测试 Si C/ Al2 O3纳米复合材料表层 V氏压痕周围残余应力的新方法。试验结果表明 ,其荧光光谱 R曲线峰频率随离压痕中心的距离大小而变化 ,压头施加在材料上的载荷的大小 ,严重影响 R曲线频率的变化。文中假定应力张量横向各向同性 ,并以加压之前材料的荧光光谱作为基值 ,确定压痕周围的残余应力。最后 ,采用等静应力解释并比较了压痕周围残余应力与压痕载荷、离压痕中心距离之间的关系。

PIEZOSPECTROSCOPIC STUDY OF RESIDUAL STRESSES AROUND INDENTATIONS IN SiC/Al2O3 NANOCOMPOSITE

A new experimental measurement of residual stresses around Vickers′ indentations on the surface of the SiC/Al2O3 nanocomposites is proposed with the aid of a Raman microprobe. Results show that the shifts of R-lines in the fluorescence spectra vary with the distance from the centre of indentation. The magnitude of load applied on the surface of the materials through the indenter influences the shifts of R-lines to great extent. The luminescence of R-lines of the materials before indenting is used to determine the residual stresses around the indentation in the materials, assuming that the stress tensor is transversely isotropic. Finally, the term of hydrostatic stress is adopted to explain and compare different residual stresses around indentations with the increase of the indenting load and the distance from the centre of indentations.