7AXX铝合金的热处理工艺

Heat treatment process of 7AXX aluminum alloy

采用正交设计试验法研究了7AXX铝合金热处理工艺,结果表明:固溶温度为470℃保温时间为1 h时合金中的过剩相已得到充分溶解。双级时效中对于材料布氏硬度值的影响因子先后顺序应为:终时效温度、终时效时间、预时效时间、预时效温度。7AXX铝合金双级时效的四因素中终时效温度是影响最终性能的主要因素,随着合金终时效温度的升高材料硬度降低。经470℃×1 h固溶+110℃×4 h+150℃×8 h热处理后,合金抗拉强度为750.27 MPa;屈服强度为562.57 MPa;断后伸长率为26.43%。

The heat treatment process of 7AXX aluminum alloy was studied using orthogonal design experiment.The results indicate that after solid solution treatments of 470 ℃×1 h,the precipitate particles of second phases decrease obviously and solute into the matrix alloy.The affecting hardness factors from strong to weak in the following order were found： second-step aging temperature,second-step aging time,first-step aging time and first-step aging temperature.The second step aging temperature is the key factor in double aging parameters,which mainly determine the final properties of 7AXX alloy.With the second-step aging temperature increasing,the alloy hardness is reduced.The reasonable heat treatment process of 7AXX alloy is two-stage aging,namely 110 ℃ for 4 hours followed by 150 ℃ for 8 h,and the ultimate tensile strength of 7AXX aluminum alloy is 750.27 MPa,the yield strength reaches 562.57 MPa,as well as the ductility reaches 26.43 %.