论文部分内容阅读
对不同含量Sc微合金化的7075合金进行了疲劳裂纹萌生、疲劳裂纹扩展的对比研究,并对其作用机理进行了分析。结果表明,随着Sc含量的增加,合金的疲劳萌生寿命和强度比都呈现先增加而后降低趋势,在Sc含量为0.24wt%时,疲劳萌生寿命和强度比最大;当应力比为0.1时,在Sc含量为0.24wt%时合金具有最大的疲劳裂纹扩展阻力,而当应力比为0.5时,在Sc含量为0.48wt%时合金具有最大的疲劳裂纹扩展阻力,这可能与细小的晶粒尺寸和较多的第二相阻碍裂纹扩展有关。总而言之,在7075合金中加入0.24wt%Sc具有最佳的疲劳性能和断裂韧性。
The fatigue crack initiation and fatigue crack propagation of 7075 alloy with different content of Sc alloyed by Sc were studied, and its mechanism of action was analyzed. The results show that with the increase of Sc content, the fatigue life and strength ratio of the alloy first increase and then decrease, and the maximum fatigue life and strength ratio are obtained when the content of Sc is 0.24wt%; when the stress ratio is 0.1, When the content of Sc is 0.24wt%, the alloy has the largest fatigue crack growth resistance, and when the stress ratio is 0.5, the alloy has the largest fatigue crack growth resistance when the content of Sc is 0.48wt%, which may be related to the small grain size And more second phase hinders crack propagation. In summary, adding 0.24 wt% Sc in 7075 alloy has the best fatigue properties and fracture toughness.