ZL205A铝合金铸件偏析缺陷分析和等级研究  

Properties and Grades of Segregation Defect in ZL205A Aluminum Alloy Castings

作　　者：陈邦峰[1] 贾泮江[1] 刘国利[1] 戴圣龙[1] 

机构地区：[1]北京航空材料研究院

出　　处：《特种铸造及有色合金》2009年第11期994-997,共4页Special Casting & Nonferrous Alloys

摘　　要：以生产过程中ZL205A铸件的偏析缺陷为研究对象,采用SEM、EDS、DSC分析手段,研究了偏析对铸件力学性能、断口形貌、组织成分和熔化温度的影响。结果表明,随着偏析缺陷级别的提高,试样抗拉强度呈下降趋势,但其值高于I级指标;试样屈服强度变化较小;试样伸长率呈快速下降,多数低于4%;试样硬度(HV)均高于100。无缺陷试样断裂主要表现为韧性断裂,偏析试样断裂为沿晶脆性断裂。偏析试样基体以α(Al)固溶体为主,晶界上分布有未完全溶解残留物Al2Cu等低熔点共晶相,共晶相熔化温度为544℃,α(Al)固溶体熔化温度为625～640℃。根据试验分析结果制订出偏析等级底片。Effects of segregation defects in the practical produced ZL205A castings on mechanical properties,fracture morphology,composition and molten temperature were analyzed by SEM(scanning electron microscope),EDS(energy dispersive spectrometer) and DSC.It is found that segregation defects have the obvious effects on mechanical properties of the alloy castings.As the grades of segregation defects increase,the trend is decreased for the tensile strength which is more than 360 MPa,the yield strength which is all more than 280 MPa changes slightly,and the elongation is quickly decreased,which is almost lower than 4%,and all micro-hardness values are higher than 100.The fracture mechanism of the samples with defects free is characterized by ductile fracture while that of one with segregation is characterized by inter-crystalline brittle fracture.The substrate composition is mainly composed of α-Al solid solution with undissolved Al2Cu phase distributed along grain boundary.Melting temperature of eutectic phase Al2Cu reaches 544℃ and melting temperature of α-Al solid solution phase is in range of 625～640℃.The cards of segregation defect grades have been presented based on property testing results.

关 键 词：偏析 ZL205A 铝合金 铸造 性能 

分 类 号：TG27[金属学及工艺—铸造]