稀土钪和铒对A356合金组织和力学性能的影响  

Effect of rare earth scandium and erbium on the microstructure and mechanical properties of A356alloy

作　　者：闫洪 YAN Hong(Kunming Metallurgical Research Institute Co.,Ltd.,Kunming 650031,Yunnan,China)

机构地区：[1]昆明冶金研究院有限公司,云南昆明650031

出　　处：《金属功能材料》2024年第6期179-183,共5页Metallic Functional Materials

基　　金：云南省社会发展科技计划-科研院所技术开发研究专项(2011CF009)。

摘　　要：研究了稀土Sc和Er对A356合金组织和力学性能的影响,通过金相组织观察、力学性能测试、扫描电子显微镜及X射线衍射分析,对比研究了不同合金组织和性能的差异,结果表明:在A356合金中复合添加质量分数为0.30%的Sc和0.28%的Er时,共晶硅的平均尺寸可减小到2.38μm,形貌也转变为细小的颗粒状;而单独添加La或AlTiB时,共晶硅平均尺寸分别是8.26和6.02μm,形貌为短棒状和尖片状,说明复合添加Sc和Er较单独添加La或AlTiB具有更好的晶粒细化作用效果,使共晶硅的晶粒尺寸显著减小,形貌也得到改善。与之相对应,A356(Sc,Er)合金的抗拉强度达到207.29MPa,伸长率是6.1%,与A356(La)合金和A356(AlTiB)合金相比,抗拉强度分别提高了40.79%和37.94%,伸长率较A356(La)合金和A356(AlTiB)合金分别提高了90.63%和60.52%,合金的强韧性得到明显提高,这不仅与共晶硅的晶粒细化有关,而且与质点Al3Sc、ScSi2和ErSi2的弥散分布相关,这些质点促进了细晶强化和弥散强化,提高了合金的力学性能。Effects of rare earth elements Sc and Er on the microstructure and mechanical properties of A356alloy were studied.The differences in microstructure and properties of different alloys were compared and studied through metallographic observation,mechanical property testing,scanning electron microscopy,and X-ray diffraction analysis.The results showed that when 0.30%Sc and 0.28%Er were added to A356alloy,the average size of eutectic silicon could be reduced to 2.38μm,and the morphology also changed to small granular shapes;When La or AlTiB is added separately,the average size of eutectic silicon is 8.26μm and 6.02μm,respectively,with short rod shaped and pointed sheet shaped morphology,indicating that the composite addition of Sc and Er has a better grain refinement effect than the single addition of La or AlTiB,significantly reducing the grain size of eutectic silicon and improving its morphology.Correspondingly,the tensile strength of A356(Sc,Er)alloy reached 207.29MPa,with an elongation of 6.1%.Compared with A356(La)alloy andA356(AlTiB)alloy,the tensile strength increased by 40.79%and 37.94%respectively,and the elongation increased by 90.63%and 60.52%respectively.The strength and toughness of the alloy were significantly improved,which is not only related to the grain refinement of eutectic silicon,but also to the dispersion distribution of Al3Sc,ScSi2,and ErSi2particles.these particles promotes fine grain strengthening and dispersion strengthening.The effect of the material has improved the mechanical properties of the alloy.

关 键 词：A356合金 Sc和Er 晶粒细化 显微组织 力学性能 

分 类 号：TG1[金属学及工艺—金属学]