Sc对A356合金热处理组织及力学性能的影响  

Effects of Sc on Microstructure and Mechanical Properties of A356 Alloy after Heat Treatment

作　　者：黄笑梅 程和法 黄吉 Huang Xiaomei;Cheng Hefa;Huang Ji(School of Mechanical Engineering,Hefei University of Technology)

机构地区：[1]合肥工业大学机械工程学院

出　　处：《特种铸造及有色合金》2023年第12期1679-1682,共4页Special Casting & Nonferrous Alloys

摘　　要：研究了0.2%~0.3%的Sc对热处理A356合金微观组织和力学性能的影响。结果表明,加入Sc后显著细化了合金中的初生α相,树枝状的初生α相转变为细小的短枝晶和颗粒状形态。同时,共晶Si也产生分枝和细化,形态由针片状变为纤维状和短棒状。加入Sc的A356合金经过530℃×6 h固溶+200℃×7 h时效处理后,共晶Si形态进一步演变成颗粒状,形状变得钝化;α-Al基体中弥散析出了Mg_(2)Si、Al_(3)Sc等强化相,显著提高了A356合金的力学性能。加入0.2%的Sc的A356合金经过热处理后,抗拉强度由不含Sc的213.9 MPa提高到292.2 MPa,伸长率由5.4%上升到7.6%。Effects of Sc on microstructure and mechanical properties of A356 alloy modified by adding 0.2%~0.3%Sc were investigated.The results indicate that primaryαdendrites are significantly refined,and the morphology is transformed from dendritic to short dendrite and spherical granular after Sc addition.Meanwhile,eutectic Si is branched and refined,of which the morphology is converted from needle sheet to fibrous and short rod shape,and further evolved into a granular shape and passivated after heat treatment of 530℃×6 h+200℃×7 h.Strengthening phase including Mg_(2)Si and Al_(3)Sc are dispersively precipitated inα-Al matrix,leading to the significant enhancement of mechanical properties.The tensile strength of the A356 alloy with 0.2%Sc is increased from 213.9 MPa to 292.2 MPa after the heat treatment,and the elongation of the alloy is increased from 5.4%to 7.6%.

关 键 词：A356合金 稀土Sc 微观组织 力学性能 

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]