摘要
研究了Nd含量对活塞用Al-Si合金的组织演变和力学性能的影响。通过金相显微镜(OM)、扫描电子显微镜(SEM)分析了Nd对该合金凝固过程中析出相的形貌和分布的影响。并对其力学性能进行了测试研究。结果表明:当Nd含量≤0.3%时,随着Nd含量的增加,α-Al基体得以细化。在Nd含量0.3%时,初生硅的等积圆直径较未添加Nd时减小了73%,当Nd含量增加至0.8%及以上时,合金中出现了富稀土相,其力学性能显著降低。Nd含量为0.3%的Al-Si合金的350℃抗拉强度较未添加Nd的Al-Si合金提高了29.8%。由于Nd元素聚集在AlCuNi相周围,造成了成分过冷,抑制了AlCuNi相的长大,AlCuNi相由粗大的骨骼状转变为细小的棒状。
The microstructure evolution and mechanical properties of Al-Si piston alloys with different Nd contents were studied. The influence of Nd on the solidification process of precipitated phase morphology and distribution of the Al-Si piston alloys were observed by the optical microscope（ OM）,scanning electron microscope（ SEM）. The mechanical properties were also tested. The results showed that when Nd content was below 0. 3%,α-Al matrix was refined. The equal-area-circle diameter of primary silicon was decreased by 73% compared with that of the Al-Si alloy without Nd addition when the content of Nd was 0. 3%. While,when the Nd content exceeded 0. 8%,a new noodle-like phase was found,which could make the mechanical properties decrease seriously. The tensile strength of 350 ℃ increased by 29. 8% compared with that of the Al-Si alloy without Nd addition when the content of Nd was 0. 3%. The constitutional supercooling caused by Nd element,which gathered around AlCuNi phase,inhibited the formation of AlCuNi phase. Hence,the shape of AlCuNi phase turned into small bars from thick bones.
作者
郭永春
郭松松
李建平
Guo Yongchun Guo Songsong Li Jianping(School of Materials and Chemical Engineering, Xi＇an Technological University, Xi＇an 710021, China)
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2017年第10期1069-1076,共8页
Chinese Journal of Rare Metals
基金
国家重点基础科研项目(613224)
陕西省教育厅重点实验室科研计划项目(16JS044)
装备预研领域基金重点项目(61409220103)
陕西省创新人才推进计划-科技创新团队(2017KCT-05)资助
关键词
铝硅合金
钕
微观组织
力学性能
变质处理
Al-Si alloy
Nd
microstructure
mechanical property
modification
