This paper aims to investigate the influence of different post-annealing cooling conditions, i.e. furnace cooling (heat treatment (HT) 1 – slow cooling) and air cooling (HT 2 – fast cooling), on the microstructure and mechanical properties of selective laser melting (SLM) built austenitic 316L stainless steel (SS).,Three sets of 316L SS samples were fabricated using a machine standard scanning strategy. Each set consists of three tensile samples and a cubic sample for microstructural investigations. Two sets were subsequently subjected to annealing HT with different cooling conditions, i.e. HT 1 and HT 2, whereas one set was used in the as-built (AB) condition. The standard metallographic techniques of X-ray diffraction, scanning electron microscopy and electron back-scattered diffraction were used to investigate the microstructural variations induced by different cooling conditions. The resultant changes in mechanical properties were also investigated.,The phase change of SLM fabricated 316L was observed to be independent of the investigated cooling conditions and all samples consist of austenite phase only. Both HT 1 and HT 2 lead to dissolved characteristic melt pools of SLM. Noticeable increase in grain size of HT 1 and HT 2 samples was also observed. Compared with AB samples, the grain size of HT 1 and HT 2 was increased by 12.5% and 50%, respectively. A decreased hardness and strength, along with an increased ductility was also observed for HT 2 samples compared with HT 1 and AB samples.,From previous studies, it has been noticed that most investigations on HT of SLM fabricated 316L were mainly focused on the HT temperature or holding time. However, the post-HT cooling rate is also an equally important factor in deciding the microstructure and mechanical properties of heat-treated components. Therefore, this paper investigates the influence of different post-annealing cooling conditions on microstructure and mechanical properties of SLM fabricated 316L components. This study provides a foundation for considering the post-HT cooling rate as an influential parameter that controls the properties of heat-treated SLM components.

Effect of post-heat treatment cooling on microstructure and mechanical properties of selective laser melting manufactured austenitic 316L stainless steel

Characterization and comparison of copper coatings developed by low pressure cold spraying and laser cladding techniques

Experimental study on characteristics of laser metal deposited Al-Si-Sn-Cu/Ti-6Al-4V composite coatings

Al/Ti5Si3-Al3Ti composite prepared via in-situ surface coating of Ti using tungsten inert gas welding

Titanium Boride and Titanium Silicide Phase Formation by High Power Diode Laser Alloying of B 4C and SiC Particles with Ti: Microstructure, Hardness and Wear Studies

M.E. Makahtha

Papers

Effects of Cooling Rate and Silicon Content on Microstructure and Mechanical Properties of Laser Deposited Ti-6Al-4V Alloy