Distribution of the composition and micromechanical properties of Be/316L stainless steel following diffusion bonding

Joining of beryllium and 316L stainless steel by hot isostatic pressing (HIP) with and without an interlayer was investigated. Metallurgical observation, scanning Auger microscopy (SAM) and nanoindentation were performed for basic characterization of bonded joints. It is shown that the diffusion depth of Be into 316L stainless steel is much greater than that of Cr, Ni or Fe into beryllium, and it is similar to 400 mum. The nanohardness of the diffusion zone on the beryllium side increases sharply due to intermetallic compounds, and the tensile strength of the Be/316L joint is < 10 MPa. For a Be/Cu/316L joint, a Cu interlayer blocks the diffusion of Fe into Be, but Ni is gathered at the Cu/316L interface and a crack is formed at this stress field. For a Be/Cu/Ni/316L joint, the diffusion depth increases further. Change of composition, mechanical property with distance in diffusion zone is smooth, and the tensile strength increases to similar to 50 MPa. Copyright (C) 2001 John Wiley & Sons, Ltd.