【摘要】 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。更多还原

【Abstract】 The fatigue crack initiation and propagation behavior of microalloyed 7075 alloys with different content of Sc were investigated,and its mechanism was also analyzed.The results show that with the increase of Sc content,the fatigue life and strength ratio of the alloy increase first and then decrease.The alloy gains the maximum fatigue life and the strength ratio of the alloy with 0.24wt%Sc content.When the stress ratio is 0.1,the alloy gets the maximum fatigue crack growth resistance with 0.24wt%Sc content,while the stress ratio is 0.5,the alloy gets the maximum fatigue crack growth resistance with the Sc content of 0.48wt%,which may be related to the fine grain size and more second phases block the crack propagation.In general,the 7075 alloy with 0.24wt%Sc has the best fatigue properties and fracture toughness.更多还原