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在相同固溶和时效条件下 ,选择 3种不同温度的水对砂铸A35 6合金进行了淬火处理 ,并对这 3种不同淬火态下的合金进行了拉伸及疲劳裂纹扩展性能研究。结果表明 ,随淬火介质温度的降低 ,淬火冷却速率提高 ,合金的强度增加 ,塑性下降 ;当应力比R较低时 ,淬火条件对合金疲劳门槛区的裂纹扩展有明显影响 ,降低淬火介质温度可以提高合金的疲劳裂纹扩展阻力。此外 ,不同淬火态合金的疲劳裂纹扩展均明显地表现出与应力比R的相关性 ,这种相关性可以用裂纹闭合来说明
Under the same conditions of solution and aging, three different temperature water were selected to quench the sand cast A356 alloy, and the tensile and fatigue crack propagation properties of the three different quenched alloys were studied. The results show that with the decrease of quenching temperature, the quenching cooling rate increases, the strength of the alloy increases and the plasticity decreases. When the stress ratio R is low, the quenching conditions have a significant effect on the crack growth in the fatigue threshold of the alloy. Improve the alloy fatigue crack growth resistance. In addition, the fatigue crack growth of different quenched alloys obviously showed the correlation with stress ratio R, which can be explained by crack closure