时效工艺对6008铝合金型材组织与性能影响

Effect of Aging Process on Microstructure and Properties of 6008 Aluminum Alloy Profiles

研究了不同时效工艺对6008铝合金挤压型材组织与性能的影响。结果表明:随时效时间的延长,型材强度先迅速增加后缓慢降低,断后伸长率先降低后趋于平稳,最佳时效工艺为175℃×8 h和200℃×3 h,屈服强度分别达到288 MPa和273 MPa,抗拉强度则分别达到304 MPa和287 MPa。随着时效时间的延长,时效析出相先快速增多后增速减缓,强度增加;随着时效过程的进行,析出相逐渐向β″相转变,此时析出相呈现包晶状态,力学性能达到最大值;继续延长时效时间,发生过时效,析出相发生粗化,力学性能下降。

The effects of different aging process on microstructure and properties of 6008 aluminum alloy extruded profiles were studied.The results showed that with the increase of aging time,the strength of profile first increased rapidly and then decreased slowly,and the elongation after fracture first decreased and then tended to be stable.The best aging process was 175℃×8 h and 200℃×3 h,the yield strength reached 288 MPa and 273 MPa respectively,and the tensile strength reached 304 MPa and 287 MPa respectively.With the extension of aging time,the precipitated phase increased rapidly at first,then slowed down,and the strength increased.With the aging process,the precipitated phase gradually increased toβ″phase transformation,the precipitated phase was peritectic state,and the mechanical properties reached the peak.Continuing to extend the aging time,over aging occured,and the precipitates coarsened and the mechanical properties delined.