|Title||Effects of particle characteristics on the microstructure and mechanical properties of 17-4 PH stainless steel fabricated by laser-powder bed fusion|
|Publication Type||Journal Article|
|Year of Publication||2018|
|Authors||Irrinki, H, Jangam, J, Pasebani, S, Badwe, S, Stitzel, J, Kate, K, Gulsoy, O, Atre, S|
|Keywords||Atomizing, Austenite, Density, Diffraction, Elongation, Energy, Flux Density, Fusion, Hardness, Martensite, Mechanical Properties, Porosity, Powder, Powder Beds, Spherical Powders, Stainless Steel, Stainless Steels, Steel, Tap Density, Tensile Strength, Theoretical Density, Ultimate Tensile Strength|
The effects of powder characteristics (powder shape, size and type) and processing conditions (laser power and scanning speed) on the mechanical properties and microstructures of laser powder bed fusion (L-PBF) 17-4 PH stainless steel were studied using four types of powders. The % theoretical density, ultimate tensile strength, hardness of L-PBF parts are sensitive to energy density and starting powder shape, size and type. The density and mechanical properties of both water and gas-atomized powders increased with increased energy density. The gas-atomized (D50 = 13 μm) powders which are spherical in shape and water-atomized (D50 = 17 μm) powders of high tap density produced low-porosity and high-density ( 97% density) L-PBF parts at low energy densities of 64 and 80 J/mm3. The increase in energy density to 104 J/mm3 resulted in high dense (97 ± 0.5%) water- and gas-atomized powders L-PBF parts. However, even at a high % theoretical density (97 ± 1%), the properties of L-PBF parts varied over a relatively large range (UTS: 500–1100 MPa; hardness: 25–39 HRC; elongation: 10–25%). This large variation in mechanical properties could be attributed the martensite and austenite phase as well as grain size in the L-PBF parts. Furthermore, the martensite and austenite phase content and of the L-PBF parts were also sensitive to the energy density and starting powder type.