冷却速度及超声振动协同作用对7085铝合金凝固组织及力学性能的影响  

Effect of cooling speed and ultrasonic vibration on solidification structure and mechanical properties of 7085 aluminum alloy

作　　者：李安庆 张立华[1,2,3] 蒋日鹏 李晓谦[1,2,3] 张昀 LI An-qing;ZHANG Li-hua;JIANG Ri-peng;LI Xiao-qian;ZHANG Yun(College of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China;State Key Laboratory of High Performance Complex Manufacturing,Central South University,Changsha 410083,China;Institute of Light Alloy Research,Central South University,Changsha 410083,China)

机构地区：[1]中南大学机电工程学院,长沙410083 [2]中南大学高性能复杂制造国家重点实验室,长沙410083 [3]中南大学轻合金研究院,长沙410083

出　　处：《材料工程》2021年第8期63-71,共9页Journal of Materials Engineering

基　　金：国家自然科学基金(51805549,52005517);湖南省科技创新计划(2020RC2002);湖南省自然科学基金(2020 JJ4703)。

摘　　要：采用炉冷、空冷、水冷3种不同的冷却方式,同时施加超声外场辅助技术,研究冷却速度、超声外场对7085铝合金凝固组织及性能的影响。采用金相显微镜、扫描电子显微镜及电子万能力学试验机对试样进行基体组织、第二相、抗拉强度和伸长率表征,并分析其凝固机理。结果表明:在炉冷、空冷、水冷3种冷却方式下,施加超声外场后各组试样α-Al微观组织细化率分别为40.2%,14.6%,21.6%,晶粒尺寸与冷却速度的拟合关系分别为:L W=154.4+25.33/v,L S=148.1+15.3/v,第二相的面积分数分别相对减少32.1%,16.9%,18.5%,第二相的平均长度及宽度也均相对有所减小,其中7085铝合金的抗拉强度分别提高21.7%,21.7%,3.6%,引入超声外场辅助技术后,相比于未施加超声组试样,7085铝合金的伸长率也得到进一步提升,分别提高31.3%,15.7%,41.4%。在超声外场及水冷协同作用下,7085铝合金微观组织及力学性能更佳。Three different cooling methods of furnace cooling,air cooling and water cooling were adopted,and ultrasonic outfield assisted technology was applied to study the effects of cooling speed and ultrasonic outfield on the solidification structure and properties of 7085 aluminum alloy.Metallographic microscope,scanning electron microscope and electronic universal mechanics testing machine were used to characterize the matrix structure,second phase,tensile strength and elongation of the samples,and the solidification mechanism was analyzed.The results show that under the above three cooling methods of furnace cooling,air cooling and water cooling,after ultrasonic field the microstructure refinement rate ofα-Al in each group is 40.2%,14.6%,and 21.6%,respectively.The fitting relationship between grain size and cooling speed is as follows:L W=154.4+25.33/v,L S=148.1+15.3/v,the second phase of the area fraction are relatively reduced by 32.1%,16.9%and 18.5%,the average length and width of the second phase are also relatively less,the tensile strength of 7085 aluminum alloy,which is increased by 21.7%,21.7%and 3.6%,respectively,after the introduction of ultrasonic outfield auxiliary technology,compared to the group without ultrasound.Elongation of 7085 aluminum alloy is further enhanced by 31.3%,15.7%and 41.4%respectively.Under the synergistic effect of ultrasonic field and water cooling,the microstructure and mechanical properties of 7085 aluminum alloy are better.

关 键 词：冷却速度 超声外场 微观组织 第二相 拟合关系 

分 类 号：TB331[一般工业技术—材料科学与工程]