冷冻铸造A356铝合金微观组织分析  

Microstructure analysis of freeze-cast A356 aluminum alloy

作　　者：杨浩秦 单忠德 刘丰 王怡飞 YANG Hao-qin;SHAN Zhong-de;LIU Feng;WANG Yi-fei(College of Materials Science and Technology,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China;State Key Laboratory of Advanced Forming Technology and Equipment,Beijing 100083,China;China Academy of Machinery Science and Technology Group Co.Ltd,Beijing 100044,China)

机构地区：[1]南京航空航天大学材料科学与技术学院,南京210016 [2]先进成形技术与装备国家重点实验室,北京100083 [3]中国机械科学研究总院集团有限公司,北京100044

出　　处：《工程科学学报》2022年第8期1331-1337,共7页Chinese Journal of Engineering

基　　金：国家重点研发计划资助项目(2021YFB3401200);国家重点研发计划资助项目(2020YFF0217703);中国机械科学研究总院集团有限公司先进成形技术与装备国家重点实验室开放基金资助项目(SKL2020008)。

摘　　要：基于数字化无模冷冻铸造精密成形技术实现了冷冻砂型的快速成形,对其浇注A356高温铝合金获得冷冻铸造平板试件.采用电子探针显微分析技术对冷冻铸造和树脂砂型铸造铸件微量元素的分布进行了表征,同时对冷冻铸造和树脂砂型铸造铸件断裂形貌进行了分析.结果表明,冷冻铸造Si元素在铝基体相中的溶解度较树脂砂型铸造显著提高,冷冻铸造较树脂砂型铸造试件中Mg元素分布均匀,树脂砂型铸造试件中出现较多的Mg元素成分偏析区;冷冻铸造试件断裂方式为韧性和脆性的混合断裂模式,树脂砂型铸造试件的断裂形貌为解理台阶破坏形貌和长方状的撕裂结构形貌,合金偏向于脆性断裂.In combination with the digital and green development needs of the foundry industry, this article proposes a digital patternless freezing casting method. In this method, mixed water green sand particles are frozen and transformed to a certain strength in a low-temperature environment, which are then directly cut through a sand mold CAD three-dimensional model. Pouring to obtain castings with dimensional accuracy that meets the requirements, this is a new technology, new process, and new method in the field of casting.With the fast development of the rapid and sub-rapid solidification technology of metals, the nonequilibrium solidification theory of liquid–solid transformation during the preparation of metals and alloy materials has been developed by leaps and bounds. Using some special nonequilibrium solidification techniques to prepare metal parts, and to make metal parts with a special structure that traditional casting does not have, can improve the materials’ properties and structures. The nonequilibrium solidification mechanism based on the freezing casting technology is not yet clear. Based on the nonequilibrium solidification process of the freezing casting principle, a higher cooling rate will considerably affect the heat transfer and mass transfer behavior of casting during solidification, which will then considerably affect the alloy micro component distribution and fracture morphology, ultimately affecting the service performance of the alloy material. Based on the digital precision forming technology of patternless frozen casting, this paper realized the rapid forming of the frozen sand mold. Frozen casting flat castings were obtained by pouring the A356 high-temperature aluminum alloy. The distribution of trace elements in frozen and resin sand castings was characterized by electron probe microanalysis,and the fracture morphology of frozen and resin sand castings was analyzed.Results show that the solubility of the Si element in the aluminum matrix phase of freeze casting is significantly higher

关 键 词：冷冻铸造 无模成形 绿色铸造 成分分布 断口形貌 

分 类 号：TG146.22[一般工业技术—材料科学与工程]