Effect of TiH2 Content Variation and Heat Treatment Process on the Preparation of Foam Steel by Laser Melting Deposition

In this experiment, Laser Melt Deposition (LMD) was used to fabricate closed cell foam stainless steel, where TiH2 was chosen as the foaming agent. The effects of different heat treatment processes on the surface morphology and thermal stability of TiH2 were investigated, as well as the effects of TiH2 heat treatment processes and TiH2 content variations on the pore size, pore distribution, and mechanical properties of the foam steel. The results show that the TiH2 decomposition temperature can be effectively increased by using graded oxidation; With the increase of TiH2 content, the porosity of the foamed stainless steel tends to increase gradually, the number of pores increases and more millimetre level pores are formed, when adding 10 wt % TiH2 (TiH2 heat treatment method selects 400°C 3 h + 480°C 2 h), the foaming effect becomes the best and the porosity reaches about 40%. In addition, compared to 316L, the foam steel has a 30 HV higher microhardness value, better compression properties and certain energy absorption properties.