Surface self-densification in boron alloyed austenitic stainless steel and its effect on corrosion and impact resistance

A boron alloyed AISI 316L, sintered in pure hydrogen at 1250°C, was investigated to study the effect of the microstructure, with particular reference to the near full dense and boride free surface layers, on corrosion resistance and impact properties. The near full dense and homogeneous austenitic surface layer results from the flow of the liquid towards the bulk of the specimens during sintering. It significantly improves the corrosion resistance, while impact properties are strongly influenced by the bulk microstructure, where the boride network creates favourable conditions for both nucleation and propagation of crack.