程亚军,冷利,宫柏山,王科飞,白鑫,张鹏,王斌

• 1:中南大学交通运输工程学院
• 2:中车长春轨道客车股份有限公司
• 3:中国科学院金属研究所

摘要(Abstract)：

采用透射电镜、显微硬度仪、拉伸试验和疲劳试验等研究了7075铝合金在欠时效(120℃×8 h)、峰时效(120℃×24 h)与过时效(120℃×48 h)状态下的微观组织、硬度、拉伸性能方面与疲劳裂纹扩展速率方面的差异。结果表明:3种时效状态的合金在高低应力强度因子范围时,疲劳裂纹扩展速率呈现不同的规律。在低应力强度因子范围时,峰时效态合金的疲劳裂纹扩展速率最高,过时效态最低;在高应力强度因子范围时,过时效态的合金表现出最优的疲劳裂纹扩展阻力,而峰时效与欠时效状态的疲劳裂纹扩展阻力相近。结合疲劳损伤能量模型、强塑积与晶界析出相差异,分析了时效时间不同引起疲劳裂纹扩展速率差异的本质原因。

关键词(KeyWords)： 7075铝合金;时效时间;疲劳裂纹扩展速率;拉伸性能;硬度

Abstract:

Keywords:

基金项目(Foundation): 中车长春轨道客车股份有限公司科技开发项目(企业内部项目)

作者(Author): 程亚军,冷利,宫柏山,王科飞,白鑫,张鹏,王斌

DOI: 10.13289/j.issn.1009-6264.2020-0465

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