Sb对A356合金组织和力学性能的影响及变质机理  

Effects of Sb on Microstructure and Tensile Properties of A356 Alloy and Analysis of Its Modification Mechanism

作　　者：曾耀华 陈宗宁[1,2] 康慧君 王雪健 王同敏[1] 

机构地区：[1]大连理工大学材料科学与工程学院、凝固控制与数字化制备技术重点实验室,辽宁大连116024 [2]大连理工大学化工学院 [3]大连理工大学原材料特种加工实验室

出　　处：《特种铸造及有色合金》2017年第10期1139-1142,共4页Special Casting & Nonferrous Alloys

基　　金：国家重点基础研究发展计划(863计划)资助项目(2016YB0701203);国家自然科学基金资助项目(51525401,51401044,51601028);中国博士后科学基金资助项目(2015M581331);中央高校基本科研基金项目;大连市顶尖及领军人才资助项目(2015R013)

摘　　要：研究了Sb含量对A356合金组织和力学性能的影响,并利用热分析、液淬试验对Sb变质机理进行了分析。结果表明,Sb变质A356合金的最佳含量为0.4%,此时共晶Si由粗大的板条状变为细小的纤维状。由于Sb的变质作用,A356合金的力学性能尤其是伸长率得以显著提高,合金的铸态伸长率最高可达11.3%,相比于未变质合金提高了79%。结果表明,Sb能够有效地降低共晶组织的形核温度,提高其形核过冷度,降低共晶组织的形核率。The effects of Sb additions on the microstructure and tensile properties of A356 alloy were investigated systematically,and thermal analysis and quenching experiments were carried out to explore the modification mechanism of Sb on Al-Si alloys.Microstructure observations show that with 0.4% Sb addition,coarse plate-like eutectic silicon phase can be converted into fibrous structure.Tensile tests show that the mechanical properties（especially the elongation）of A356 alloys are improved greatly.The maximum elongation value reaches 11.3% under as-cast condition,which is 79% higher than that of the unmodified alloy.Thermal analysis and quenching structure observation reveal that the nucleation temperature of eutectic Si phase is continuously decreased with Sb additions,therefore the nucleation undercooling can be increased to decrease nucleation rate of eutectic Si phase.

关 键 词：Sb变质 A356合金 力学性能 变质机理 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG113.25[金属学及工艺—金属材料]