双级机械搅拌铸造SiC_p/A357复合材料的工艺及性能  

Properties of SiC_p/A357 Composites Fabricated by Double-deck Mechanical Stirring Casting

作　　者：张桢林 张志峰[1] 徐骏[1] 王亚宝[1] 张浩[1] 毛卫民[2] 

机构地区：[1]北京有色金属研究总院国家有色金属复合材料工程技术研究中心 [2]北京科技大学材料科学与工程学院

出　　处：《特种铸造及有色合金》2017年第6期598-601,共4页Special Casting & Nonferrous Alloys

基　　金：国家国际科技合作计划资助项目(2015DFA51230)

摘　　要：以A357铝合金和SiC_p粉作为原料,采用双级搅拌桨在不同工艺参数下对SiC_p含量为20%的A357复合材料进行搅拌铸造,研究了不同工艺参数对SiC_p分布均匀性的影响。对制得的SiC_p/A357复合材料进行T6热处理,采用扫描电镜、硬度测试及拉伸试验,分析了热处理前后组织和力学性能的变化。结果表明,采用双级搅拌桨在搅拌温度为610℃,搅拌转速为800 r/min,搅拌时间为20 min下制备的复合材料中SiC_p分布均匀性最佳。经T6热处理后,复合材料的抗拉强度和硬度明显上升,抗拉强度达到345 MPa,硬度(HB)为123.3,相比铸态分别提高66%和48.6%。断口分析表明,SiC_p/A357复合材料的断裂机制为界面脱粘、Si C颗粒的断裂和基体合金的韧性断裂的混合机制。Through using A357 alloy and SiC micro powder as raw material, SiCp/A357 composites with 20% SiCp particles were prepared with different technological parameters of mechanical stirring casting using double-deck impeller. The effects of technological parameters on the uniformity of SiCp in the composites prepared were investigated. The SiCp/A357 composites were treated by T6 treatment to analyze the influence of heat treatment on microstructure and mechanical properties of the composites by SEM, Brinell hardness and tensile test. The results reveal that the uniform distribution of SiCp using doubledeck impeller can be observed at 800 r/min for 30 rain and 610℃. After T6 heat treatment, the tensile strength and hardness of the composites reach 345 MPa and 123.3 HB, increased by 66% and 48.6%, respectively, compared with those of as-cast ones. The fracture analysis reveals that the fracture mecha- nism of the composites is characterized by a mixed modes including interface decohesion between A357 and SiCp, SiCp fracture and ductile fracture of A357 matrix.

关 键 词：SiCp/A357复合材料 搅拌铸造 显微组织 力学性能 热处理 

分 类 号：TB333[一般工业技术—材料科学与工程]