| One requirement for alloys used in fusion reactors is sound joining. Thus, this study includes two major portions, first is the design of an induction brazing process for Glidcop Al-15, and second is the properties and weldability of Fe-Cr-Mn-C steels.; I. The Glidcop Al-15, a dispersion strengthened copper-alumina alloy, has been selected for possible use in limiters of tokamak fusion reactors. This choice was made because of the alloy's ability to retain a cold worked structure at elevated temperatures and because of its high heat carrying capacity, and high electrical conductivity. Furnace brazing of this alloy requires long times at high temperatures. The objective of this work centered on minimizing the time required at elevated temperatures during the brazing process. Overlap and butt brazed joints were produced by using a 50 kW induction furnace and a silver based filler alloy. Induction brazing was conducted in less than 17 seconds and without the use of a protective atmosphere. Silver diffusion was used to estimate the amount of filler diffusion and to develop a grain size model. Tensile, microhardness and fatigue tests were conducted to evaluate the mechanical properties of the brazed alloy. The results indicated that a satisfactory induction brazing process can be achieved and reasonable mechanical properties can be obtained with the use of a silver filler alloy.; II. A Russian steel, Fe-11.6Cr-19.3Mn-0.081C and an U.S. steel, Fe-12.1Cr-19.4Mn-0.24C were developed as possible candidates for the first wall and blanket structures of a tokamak fusion reactor. These steels were developed to reduce the long-term radioactivity induced by reactor irradiation for easier waste disposal. Manganese is used as a replacement for nickel while W, Ti, V, C, B and P are added to improve strength and irradiation resistance. A gas tungsten arc welding (GTAW) process was used and the welded microstructure and mechanical properties were characterized. Tensile, microhardness and weld bend tests were conducted to evaluate the mechanical properties of the welded steels. The results indicated that sound welds and good mechanical properties were achieved by gas tungsten arc welding of both the Russian and the U.S. steels. |
