固溶时间对半固态挤压成形Al-17Si-4Cu-0.5Mg合金组织及力学性能的影响  

Effect of solution time on microstructure and mechanical properties of Al-17Si-4Cu-0.5Mg alloy formed by semisolid squeeze casting

作　　者：郝建飞[1] 于宝义[1] 罗惠馨 史原脊 李润霞 HAO Jian-fei;YU Bao-yi;LUO Hui-xin;SHI Yuan-ji;LI Run-xia(School of Materials Science and Engineering,Shenyang University of Technology,Shenyang 110870,China;School of Materials Science and Engineering,Dongguan University of Technology,Dongguan 523808,Guangdong,China)

机构地区：[1]沈阳工业大学材料科学与工程学院,沈阳110870 [2]东莞理工学院材料科学与工程学院,广东东莞523808

出　　处：《材料工程》2021年第10期63-71,共9页Journal of Materials Engineering

基　　金：国家自然科学基金项目(51974092);广东省基础与应用基础研究基金区域联合基金项目(2020B1515120065);广东省教育厅普通高校重点领域专项(2020ZDZX2058);广东省重点领域研发计划项目(2020B010186002)。

摘　　要：采用半固态挤压成形工艺制备过共晶Al-17Si-4Cu-0.5Mg合金,研究固溶时间对过共晶Al-17Si-4Cu-0.5Mg合金组织及性能的影响。结果表明,随着固溶时间的增加,Si相出现球化,固溶时间为10 h时,共晶Si的圆整度为0.72。铸态下Si相周围富集较高浓度的Cu元素,固溶1 h后,Cu元素快速固溶到基体中。固溶时间从1 h增加到16 h,在XRD曲线上的θ(Al_(2)Cu)和Q(Al_(5)Si_(6)Cu_(2)Mg_(8))相的衍射峰强降低,合金基体中的位错密度大量减少。经180℃,时效处理12 h后,组织中析出针状的θ′相和短棒状的Q′相。随着固溶时间的增加,合金强度值呈现“双峰”现象。固溶1 h后,合金的抗拉强度为269 MPa,屈服强度为233 MPa,与未热处理合金相比,抗拉强度和屈服强度分别提高了43.3%和42.7%,合金强度的提高是由于在固溶初期基体中仍有较大的位错密度,时效处理后析出相对位错有较强的钉扎阻碍作用。固溶时间为10 h时,合金的抗拉强度为311 MPa,屈服强度为263 MPa,达到第二个强度峰值,Si相的圆整化和细小析出相的弥散强化作用是形成第二个强度峰的主要原因。The effects of hypereutectic Al-17Si-4Cu-0.5Mg alloy were prepared by semisolid extrusion.The effect of solution time on microstructure and properties of hypereutectic Al-17Si-4Cu-0.5Mg alloy was studied.Results show that spheroidization occurs in the Si phase with the increase of solution time.When the solution time reaches 10 h,the circularity of eutectic Si is 0.72.High concentration of Cu element is enriched around Si phase in as cast state.After solution for 1 h,Cu element is rapidly dissolved into the matrix.As solution time is increased from 1 h to 16 h,the diffraction peak intensity ofθ(Al_(2)Cu)and Q(Al_(5)Si_(6)Cu_(2)Mg_(8))phases on the XRD curve is decreased,and the dislocation density in the alloy matrix is greatly reduced.After aging treatment at 180℃is performed on the solution treated samples,theθ′and Q′phases precipitate.As the solution time increases,the alloy strength value shows a“double peak”phenomenon.After solution treatment for 1 h,the tensile strength of the alloy reaches 269 MPa and the yield strength is 233 MPa.Compared with the unheated alloy,they are increased by 43.3%and 42.7%,respectively.This is mainly because there is still larger dislocation density in the matrix at the initial stage of solution,and the precipitation has stronger pinning hindrance to the dislocation after aging treatment.When the solution time is 10 h,the tensile strength and yield strength of the alloy reach 311 MPa and 263 MPa,respectively.The roundness of Si phase and the strengthening effect of fine precipitates are the main reasons for the formation of the second strength peak.

关 键 词：固溶时间 半固态挤压铸造 AL-SI-CU-MG合金 微观组织 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG249.2[金属学及工艺—金属材料]