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通过小能量多次冲击方法研究了五种常用冲压模具用硬质合金的冲击疲劳行为,利用Weibull统计分布分析材料的冲击疲劳性能,采用扫描电镜观察断口形貌。试验结果表明:从硬质合金多次冲击疲劳试验的断口可观察到特征明显不同的三个区域——裂纹稳定生长的微粗糙区,裂纹激烈扩展的光亮区,最后断裂的平滑区。晶粒度1.4μm、钴含量20%的硬质合金,其耐冲击疲劳性能最好。
The impact fatigue behavior of five commonly used cemented carbide for stamping dies was studied by the small energy multiple impact method. The impact fatigue properties of the cemented carbide were analyzed by Weibull statistical distribution. The fracture morphology was observed by scanning electron microscopy. The experimental results show that three regions with obviously different features, that is, the micro-rough zone with stable crack growth, the bright area with intense crack propagation and the smooth zone with the last fracture, can be observed from the fracture of cemented carbide after repeated impact fatigue test. The grain size of 1.4μm, cobalt content of 20% of the cemented carbide, the best impact fatigue resistance.