STRUCTURE AND PROPERTIES OF WELDED LONG-RANGE-ORDERED ALLOYS.

Sound autogenous welds can be produced readily in thin sheets of the (Fe,Ni)//3(V,Ti) and (Fe,Co)//3(V,Ti) long-range-ordered (LRO) alloys. Welds of (Fe,Ni)//3(V,Ti) were disordered, but the tensile properties were not adversely affected. A reordering heat treatment restored the weldment properties to those of the base metal. Welds of (Fe,Co)//3(V,Ti) remained ordered after the weld thermal cycle. Tensile properties similar to those of the base metal and a more uniform hardness profile can be produced by using a postweld heat treatment. In many potential applications at elevated temperatures, the use of a post-weld reordering heat treatment would be unnecessary for both alloys because the weldment would reorder itself during service. Factors that seem to influence the weldment properties include ordered domain size and precipitation of carbides.