Effect of Graphite Content on Diffusion Bonding of Iron Powder Compacts under Applied Pressure

Diffusion bonding between Fe powder compacts was carried out to investigate an effect of graphite content in powder on bonding strength at several bonding temperatures and bonding pressures. The results are as follows: shear strength of both inside and joint of Fe powder compact subjected to diffusion bonding has a maximum value at graphite content of 0.2 wt.% at overall bonding temperatures from 973-1273K and bonding pressures from 10-60 MPa; subsequent sintering at a temperature of 1323K and for a time of 3.6 ks remarkably improves the shear strength of both inside and joint, which increases linearly with increasing graphite content; and critical bonding condition to obtain 100% of joint efficiency is a temperature of 1073-1173K and a pressure of 20-40 MPa for all graphite contents up to 0.8 wt.%.