DC铸造7075铝合金微观偏析的量化分析  

Quantitative analysis of microsegregation in DC cast 7075 aluminum alloy

作　　者：陈丹丹[1] 张海涛[1] 蒋会学[1] 崔建忠[1] 

机构地区：[1]东北大学材料电磁过程教育部重点实验室,沈阳110819

出　　处：《材料与冶金学报》2011年第3期220-225,共6页Journal of Materials and Metallurgy

摘　　要：采用直接水冷半连续铸造(DC铸造)工艺制备7075铝合金铸锭.利用电子探针(EPMA)观察合金元素在样品中的分布,并通过绘制元素分布图判断合金元素在基体中的分布趋势.由于合金相的形成,Zn,Mg和Cu元素易在晶界偏聚;Cr和Ti作为形核质点,易在晶粒中心偏聚.利用5种排序方法处理收集到的电子探针数据,分别绘制成分曲线.通过比较成分曲线和排序方法适合度(GOF系数)得出,等级排序法和加权等级排序法比较适于分析DC铸造7075铝合金的微观偏析.分析计算得到的初始溶质分配系数kinit发现,F-G排序法夸大了合金元素的微观偏析,而加权等级排序法则减小了合金元素微观偏析的趋势.The 7075 aluminum alloy was prepared by the direct chill semi-continuous casting.The distributions of the alloying elements were measured by the electro probe microanalysis（EPMA）,and the solute-solvent correlation relationships were drawn.It was found that the Zn,Mg and Cu elements were segregated in the grain boundary because of the formation of the alloy phases,and the Cr and Ti elements which contributed to the nucleation segregated in the core of the dendrite.The EPMA data were sorted by five schemes,the concentration profiles were plotted and the effectiveness of the sort schemes was compared.The rank sorts and the weighted interval rank sorts were more appropriate for estimating the microsegregation of the DC cast 7075 aluminum alloy.The initial elemental partition coefficients kinit were calculated by linearising the Scheil model.The results indicated that the F-G sorts magnified the microsegregation of the alloying elements while the weighted interval rank sorts decreased the tendency of microsegregation.

关 键 词：铝合金 DC铸造 微观偏析 排序方法 

分 类 号：TG14[一般工业技术—材料科学与工程]