Punch-shear tests and size effects for evaluating the shear strength of machinable ceramics
Punch-shear tests and size effects for evaluating the shear strength of machinable ceramics
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DOI：
10.3139/146.017960
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发表时间：
2004-05
影响因子：
0.8
通讯作者：
Y. Bao;Haibin Zhang;Yanchun Zhou
中科院分区：
文献类型：
--
作者：
Y. Bao;Haibin Zhang;Yanchun Zhou
摘要采用不同的试样厚度和冲孔直径进行冲孔剪切试验，研究尺寸对可切削陶瓷抗剪强度评价的影响。试样厚度与冲孔直径之比定义为在一定范围内对所测抗剪强度有强烈影响的相对厚度。研究发现，在相对厚度上存在一个阈值（Ti3AlC2为~ 0.1，Ti3SiC2为~ 0.13），在此阈值以上，抗剪强度随厚度的增加而线性增加。该阈值为有效的冲剪试验提供了厚度要求，在此要求下，分别使用3 mm和1.8 mm的冲头直径获得了稳定的抗剪强度。不同加载速率下的试验表明，冲剪试验测得的抗剪强度几乎不受加载速率的影响。通过光学和扫描电镜观察，分析了尺寸效应的机理。
Abstract Various sample thicknesses and punch diameters were used in punch-shear tests for investigating the size effects in evaluating the shear strength of machinable ceramics. The ratio of the sample thickness to the punch diameter was defined as the relative thickness that strongly affects the measured shear strength in a certain range. It was found that there was a threshold value in the relative thicknesses (~ 0.1 for Ti3AlC2 and ~ 0.13 for Ti3SiC2) above which the measured shear strength increased linearly with increasing thickness. The threshold provided a thickness-requirement for valid punch-shear tests, and stable shear strength was obtained under this requirement using 3 mm and 1.8 mm punch diameters, respectively. Experiments using various loading rates suggested that the shear strength measured by the punch-shear test was almost immune from the loading rates. The mechanism of the size effects was analysed through optical and SEM observations.