Joining MoSi2 to 316L stainless steel

The feasibility of joining MoSi2 to 316L stainless steel using active brazing techniques was investigated using two interlayer systems: cusil/Nb/cusil and cusil/Ni/cusil (where cusil is a commercially available Cu-Ag eutectic). Dense, uniform joints were obtained with the cusil/Nb/cusil interlayer system, because the coefficient of thermal expansion (CTE) of niobium closely matched that of NoSi2 over a wide temperature range. Matching the CTEs of MoSi2 and the interlayer material shielded the low-toughness MoSi2 from residual stresses formed during cooling from the joint-processing temperature (830 degrees C). The cusil/Nb/cusil interlayer, however, failed to produce adequate joints because of the large CTE difference between nickel and MoSi2.