Effect of quenching cooling rate on residual stress and microstructure evolution of 6061 aluminum alloy  

淬火冷却速率对6061铝合金残余应力及微观组织演变的影响

作　　者：HUANG Ke YI You-ping HUANG Shi-quan HE Hai-lin LIU Jie HUA Hong-en TANG Yun-jian 黄珂;易幼平;黄始全;何海林;刘杰;华宏恩;唐云建(Research Institute of Light Alloy,Central South University,Changsha 410083,China;State Key Laboratory of Precision Manufacturing for Extreme Service Performance,Changsha 410083,China;School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China)

机构地区：[1]Research Institute of Light Alloy,Central South University,Changsha 410083,China [2]State Key Laboratory of Precision Manufacturing for Extreme Service Performance,Changsha 410083,China [3]School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China

出　　处：《Journal of Central South University》2024年第7期2167-2180,共14页中南大学学报（英文版）

基　　金：Project(2021GK1040)supported by the Major Projects of Scientific and Technology Innovation of Hunan Province,China;Project(52375398)supported by the National Natural Science Foundation of China。

摘　　要：In this study,the cooling rate was manipulated by quenching with water of different temperatures(30,60 and 100℃).Surface and internal residual stresses in the quenched 6061 aluminum alloy samples were measured using hole-drilling and crack compliance methods,respectively.Then,the processability of the quenched samples was evaluated at cryogenic temperatures.The mechanical properties of the as-aged samples were assessed,and microstructure evolution was analyzed.The surface residual stresses of samples W30℃,W60℃and W100℃is−178.7,−161.7 and−117.2 MPa,respectively along x-direction,respectively;and−191.2,−172.1 and−126.2 MPa,respectively along y-direction.The sample quenched in boiling water displaying the lowest residual stress(~34%and~60%reduction in the surface and core).The generation and distribution of quenching residual stress could be attributed to the lattice distortion gradient.Desirable plasticity was also exhibited in the samples with relatively low quenching cooling rates at cryogenic temperatures.The strengthes of the as-aged samples are 291.2 to 270.1 MPa as the quenching water temperature increase from 30℃to 100℃.Fine and homogeneous β"phases were observed in the as-aged sample quenched with boiling water due to the clusters and Guinier-Preston zones(GP zones)premature precipitated during quenching process.本研究采用不同水温(30、60和100℃)淬火控制冷却速率并通过钻孔法和裂纹柔度法测量了淬火态6061铝合金样品的表面和内部残余应力,以评估淬火样品的可加工性;测试了时效样品的力学性能,观察样品的微观组织以分析其演变规律。结果表明:样品W30℃、W60℃和W100℃沿x方向的表面残余应力分别为−178.7、−161.7和−117.2 MPa;沿y方向的表面残余应力分别为−191.2、−172.1和−126.2 MPa。沸水淬火试样的残余应力最低(表面和芯部减少约34%和60%)。淬火残余应力的产生和分布机制可归因于晶格畸变梯度。力学性能测试结果表明,淬火冷却速率对试样的塑性没有明显影响,随着淬火水温度从30℃上升到100℃,时效样品的强度从291.2降低到270.1 MPa。由于团簇和Guinier-Preston区(GP区)在沸水淬火过程中提前析出,时效后样品中观察到细小且均匀分布的βʺ相。

关 键 词：6061 aluminum alloy residual stress cooling rate cryogenic cooling mechanical properties microstructure evolution 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG156.3[金属学及工艺—金属材料]