Partially Melted Zone in Aluminum Welds

本程序的目的是为了更好地了解铝合金气体金属电弧焊过程中部分熔化区的形成、组织和性能。在铝-4.5%铜合金上进行了气体金属弧焊，研究了其晶界组织，确定了温度梯度和生长速率。通过扫描透射电子显微镜和纳米压痕测定了溶质和硬度在晶界上的分布。研究了脉冲气体金属弧焊的热效应，确定了热效应对晶界液化的影响。效益是基于较低的热量输入产生的脉冲过程。焊缝结构的Gleeble模拟为晶粒凝固的样品提供了可控的、已知的热循环和近一维的热流。气体金属电弧焊是应用最广泛的铝合金焊接工艺。该研究已应用于全铝车身等铝质结构的焊接，是未来汽车轻量化的一个方向。＊＊＊

9803589 Kou The object of this program is to better understand the formation, structure and properties of the partially melted zone formed during gas metal arc welding of aluminum alloys. Gas metal arc welds are made on an aluminum-4.5% copper alloy to examine the grain boundary structure and determine the temperature gradient and growth rate. Solute and hardness distributions are determined across grain boundaries by scanning transmission electron microscopy and nano indentation. Thermal effects are explored using pulsed gas metal arc welding to determine effect on grain boundary liquation. Benefits are expected based on the lower heat input produced by the pulsing process. Gleeble simulation of the weld structure provides controlled, known thermal cycles and nearly one dimensional heat flow to samples undergoing grain solidification. %%% Gas metal arc welding is the most widely used process for welding aluminum alloys. The research has application to the welding of aluminum structures, such as an all-aluminum automobile body, one direction pursued to reduce the weight of future automobiles. ***