摘要
对A356合金进行细化变质处理是提高其力学性能的重要途径之一。用新型Al-Ti-La细化剂和Al-10Sr变质剂处理A356合金熔体,研究了细化变质保温时间对铸态A356合金显微组织和力学性能的影响。结果表明,当保温时间为15 min,采用Al-Ti-La细化剂和Al-10Sr变质剂复合处理A356合金时,铸态A356合金组织中α-Al的二次枝晶臂间距由31.10μm减小到15.56μm,减小了49.96%,共晶Si形貌由粗大针片状转变为细小短棒状和颗粒状。随着α-Al和共晶Si相形貌的改善,铸态A356合金的抗拉强度由169.67 MPa提高至216.33 MPa,提高了27.50%,伸长率由4.47%提高至10.53%,提高了135.57%,合金的维氏硬度也由56.37 HV提高到62.03 HV,提高了10.04%。断裂方式由穿晶断裂向沿晶断裂转变,合金的塑韧性得到明显改善。
Refining and modifying A356 alloy is one of the important ways to improve its mechanical properties.In this paper,A356 alloy melt was treated with a new Al-Ti-La refiner and Al-10Sr modifier,and the effect of holding time on the microstructure and mechanical properties of as-cast A356 alloy was studied.The results show that when the holding time is 15 min and the A356 alloy is treated with Al-Ti-La refiner and Al-10Sr modifier,the secondary dendrite arm spacing ofα-Al in the as-cast A356 alloy is reduced from 31.10μm to 15.56μm,which is reduced by 49.96%,and the eutectic Si morphology is changed from coarse needle flake to fine short rod and granular.With the improvement ofα-Al and eutectic Si phase morphology,the tensile strength of as-cast A356 alloy increased from 169.67 MPa to 216.33 MPa,increased by 27.50%,the elongation increased from 4.47%to 10.53%,increased by 135.57%,and the Vickers hardness of the alloy also increased from 56.37 HV to 62.03 HV,increased by 10.04%.The fracture mode changes from trans granular fracture to intergranular fracture,and the plasticity and toughness of the alloy are obviously improved.
作者
胡立雯
徐梅
孙建英
余海存
丁万武
HU Liwen;XU Mei;SUN Jianying;YU Haicun;DING Wanwu(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China)
出处
《有色金属工程》
CAS
北大核心
2023年第7期31-40,共10页
Nonferrous Metals Engineering
基金
国家自然科学基金资助项目(52161006)
中国博士后科学基金项目(2019M653896XB)
甘肃省教育厅产业支持计划项目(2021CYZC-23)
甘肃省重点研发计划项目(21YF5GD183)。
关键词
A356合金
细化变质保温时间
显微组织
力学性能
A356 alloy
refinement modification holding time
microstructure
mechanical properties
