Mechanical properties of a novel plymetal manufactured by laser-assisted direct metal deposition

Abstract

Plymetal is the term used here to describe a composite structure where more than one solid metals are joined or pressed to gain unique set of properties. Mostly flat plates are used, which are then bonded together to form sheets for further forming processes. In this work, a novel plymetal is designed to create a structure with alternating layers of metals both in radial and in axial directions. In the radial direction, the plymetal was conceived by having a cylinder surrounded by annular structure of alternate material. In the axial direction, the centre cylindrical material is changed, followed by annular structure of alternate material. Such a plymetal is realised by laser-assisted direct metal deposition additive manufacturing technology. Two different metal powders, AISI H13 tool steel and AISI 316L stainless steel, were used to create the plymetal. The uniaxial compressive test was performed on the plymetal, and the results were compared with the individual solid structure of H13 tool steel and 316L stainless steel, also made by direct metal deposition. Young’s modulus, yield strength and yield strain of the samples were determined in compression. The dual modulus of elasticity in the region before yielding was observed in all samples. An analytical equation to calculate Young’s modulus of the plymetal based on a stiffness method was also derived. Microstructure of the plymetal was observed through optical and scanning electron microscopy, which revealed perfect bonding between the two metals and small pores with sizes less than 1 μm. It is expected that the variant of plymetal will be able to give better tuneable control on the mechanical properties for numerous applications.