Mechanical properties and microstructure of laser-cladding additively manufactured 316L stainless steel sheets

Abstract

Laser cladding (LC) technique, as one of advanced additive manufacturing techniques, has been proved to own great potential to be applied for building and civil engineering. By using the LC technique, the laser cladding sheet (LC sheet) can be realised by overlapping track-by-track in a layer and layer-by-layer through the depth of the sheet. However, the lack of knowledge on the structural performance of this LC sheet impedes the application of the LC technique in building and civil infrastructure. Accordingly, this paper presents the first results of a wide experimental campaign aimed at evaluating the material behaviour of LC sheets. In this investigation, the mechanical properties, degree of anisotropy and microstructure of the LC sheets produced by using commercial 316 L stainless steel powder were studied. Through tensile tests, the influences of the scanning pattern, specimen orientation and thickness on the mechanical properties of the LC sheets were investigated. The test results revealed the elastic isotropy for the elastic modulus and Poisson's ratio, and the plastic anisotropy for the proof stresses, ultimate stress and elongation, but the degree of anisotropy for most of the plastic mechanical properties was less than 20%. The microindentation hardness of the LC sheets was measured, and the linear correlation between the ultimate strength and hardness of the LC sheets was established. Microstructure analyses using metallographic and SEM tests demonstrated that the observations on the mechanical properties could be explained and rationalised by the specific microstructural features.