Fabrication and mechanical properties of composite structure by warm spraying of Zr-base metallic glass

Metallic glasses are highly attractive because of their superior strength, relatively low Young's modulus and superb corrosion resistance[S1], etc. By combining a metallic glass with different materials, synergy effect can be expected in the mechanical properties and corrosion resistance, for example. Fabricating a thick metallic glass layer on a substrate material by thermal spray process is one way to bond these materials. In such practice, however, the temperature of the sprayed metallic glass and that of the substrate must be kept relatively low in order to avoid crystallization and/or oxidation of the amorphous deposits, Warm Spray is a modified version of HVOF spraying developed by National Institute for Materials Science (NIMS) suited for spraying of heat sensitive feedstock materials. In the process, high-velocity solid particles heated to the temperatures below its melting point are projected on to the substrate. A Zr-base metallic glass powder was warm sprayed onto cylindrical substrates of 316L stainless steel to various thicknesses. Negligible crystallization and oxidation were observed in the deposited layer of the glass alloy. The linear relationship between the thickness of the glass alloy layer and the Young's modulus of the composite bar demonstrated that the mechanical property of such composite structures can be controlled.