CAJ | 학술논문

本文通过加入不同富铈稀土变质剂和Sr对 A356铸铝进行变质，分析了枝晶及共晶硅形貌，测试了几组材料的延伸率、拉伸强度和疲劳行为。试验及分析表明：变质剂对微结构的主要作用是改善了枝晶分布的均匀度，使共晶硅形态趋向短粗和圆棒状。随变质剂加入量的增加，A356合金的拉伸强度和延伸率逐渐增加。变质剂对A356铝合金的低周疲劳性能影响甚微，而提高了高周疲劳寿命。综合分析表明，变质剂对枝晶组织的均匀化和对共晶硅形貌的变化减小了初始缺陷尺寸，对疲劳裂纹萌生寿命的提高有显著影响。
본문통과가입불동부시희토변질제화Sr대 A356주려진행변질，분석료지정급공정규형모，측시료궤조재료적연신솔、랍신강도화피로행위。시험급분석표명：변질제대미결구적주요작용시개선료지정분포적균균도，사공정규형태추향단조화원봉상。수변질제가입량적증가，A356합금적랍신강도화연신솔축점증가。변질제대A356려합금적저주피로성능영향심미，이제고료고주피로수명。종합분석표명，변질제대지정조직적균균화화대공정규형모적변화감소료초시결함척촌，대피로렬문맹생수명적제고유현저영향。
The effect of Ce-rich rare earth and Strontium addition on A356 cast Aluminum alloy is investigated in this paper .Dendrites and eutectic silicon morphology are observed under optical micro-scope .Tensile strength ,elongation rate and fatigue properties of alloys with different rare earth addi-tion are obtained .Results show that the modificators increase the uniformity of the dendrites ,w hile the morphology of eutectic silicon tends to be more short and round .Tensile strength and elongation rate both increase with the increasing of rare earth and Strontium .Although the high -cycle-fatigue is increased with the increasing of the modificators ,low -cycle-fatigue life of A356 alloy remains un-affected .Analysis shows that the modificators affect the initial defect size and have a significant effect on the improvement of the fatigue crack initiation life .