【摘要】 通过对不同热暴露制度下2A12铝合金的常温拉伸力学性能测试和微观组织演变的观察,分析热暴露制度对预变形该铝合金微观组织和性能的影响。结果表明在120℃热暴露500 h后2A12合金力学性能提升,热暴露温度提高到160℃、200℃,合金性能直线下降。200℃热暴露100 h时合金强度损失严重,之后缓慢下降。T8态合金中S相的尺寸比T6态更加均匀,粗化速率更低。T8态合金由于大量位错的诱导,溶质充分析出,基体浓度已经降低到一定程度。而T6态合金基体浓度高于T8态合金,加之较小相体的溶解可以提供溶质,其S相更容易粗化,进而降低了合金强度。更多还原

【Abstract】 The microstructure and tensile properties at different thermal exposure conditions of pre-stretching 2A12 aluminum alloy drilling pipe were studied by means of tensile test and TEM analysis.The results show that the mechanical properties of 2A12 alloy exposed at 120 ℃ for 500 h are improved,but dropped dramatically when exposed at 160 ℃ and 200 ℃.Alloy lost strength rapidly when exposed at 200 ℃ for 100 h,with a slighter decline since then.S phase possesses more uniform size distribution in T8 alloys than in T6 alloys,exhibiting slower coarsening rate.It is argued that supplement of solute is always needed for coarsening of the precipitates,and solute concentration in the matrix of T8 alloy is lower than that of T6 alloy due to full precipitation induced by high density dislocations in T8 alloy.S phase in T6 alloys coarsens easier than that in T8 alloys by the dissolution of finer precipitates,thus the strength declines.更多还原