冷却速度对ZL702A微观组织与宏观力学性能的影响  

Effects of Cooling Rates on Microstructure and Macromechanical Properties of ZL702A

作　　者：季显坤 姚婷 闫志义 马志军[4] 崔文 陈家慧 夏峰[4] JI Xiankun;YAO Ting;YAN Zhiyi;MA Zhijun;CUI Wen;CHEN Jiahui;XIA Feng(AECC Hunan Aviation Powerplant Research Institute,Zhuzhou 412002,China;Shaanxi Nonferrous Yulin New Material Group Co.,Ltd.,Yulin 719099,China;Shanxi Diesel Engine Industry Co.,Ltd.,Datong 037036,China;School of Materials Science and Chemical Engineering,Xi'an Technological University,Xi'an 710021,China)

机构地区：[1]中国航发湖南动力机械研究所,湖南株洲412002 [2]陕西有色榆林新材料集团有限责任公司,陕西榆林719099 [3]山西柴油机工业有限责任公司,山西大同037036 [4]西安工业大学材料与化工学院,陕西西安710021

出　　处：《热加工工艺》2023年第12期81-85,共5页Hot Working Technology

基　　金：国家装发研究项目(KY-1044-2022-0281);陕西省横向联合项目(YJZX-2021-002);陕西省高校青年创新团队项目(K20220185)。

摘　　要：采用不同内腔尺寸(40、30、20、10mm)的铜模进行重力浇注,制备冷却速度分别为15、17、37、104K/s的ZL702A试样。通过光学显微镜和扫描电镜对其微观组织进行分析,同时进行拉伸力学性能测试。结果表明,随着冷却速度的提升,α-Al晶粒尺寸逐渐减小,由167.5μm降到了58.3μm;二次枝晶臂间距从19.4μm下降至13.8μm,枝晶得到显著细化。随着冷却速度从15K/s到104K/s,室温平均抗拉强度提升5%,平均断后伸长率提升14.6%;高温平均抗拉强度提升18.0%,平均断后伸长率增幅达到42.9%。另外,α-Al晶粒尺寸对材料的室温抗拉强度影响较大,而二次枝晶臂间距对材料的高温拉伸性能影响较大。随着冷却速度增大,过冷度提高,增加了合金在凝固过程中的形核率,细化了α-Al晶粒及其组织,从而达到同时提升铸件强韧性之目的。ZL702A samples were prepared at cooling rates of 15,17,37 and 104 K/s by gravity casting of copper molds with different inner cavity sizes(40,30,20 and 10 mm).The microstructure was analyzed by optical microscope and scanning electron microscope,and the tensile mechanical properties were tested at the same time.The results show that with the increase of cooling rate,α-Al grain size gradually decreases from 167.5 μm to 58.3 μm;secondary dendrite arm spacing drops from 19.4 μm to 13.8 μm.The dendrites are significantly refined.With the cooling rate from 15 K/s to 104 K/s,the average tensile strength at room temperature increases by 5% and the average elongation after fracture increases by 14.6%;the average tensile strength at high temperature increases by 18.0%,and the average elongation after fracture increases by 42.9%.In addition,the α-Al grain size has a great influence on the tensile strength of the material at room temperature,while the secondary dendrite arm spacing has a great influence on the high temperature tensile properties of the material.As the cooling rate increases,the supercooling degree increases,the nucleation rate of the alloy during solidification increases,and the α-Al grains and their structures are refined,thereby achieving the purpose of simultaneously improving the strength and toughness of the casting.

关 键 词：微观组织 冷却速率 二次枝晶臂间距 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程]