Effect Of Construction Angle On Microstructure/Properties Of Stainless Steel And Aluminum Alloy Prepared By Selective Laser Melting

Selective laser melting(SLM)is a main metal Additive Manufacturing technology currently.According to CAD data,metal powder is sintered layer by layer,and the three-dimensional model is directly manufactured into parts.Therefore,basing on this layered scanning method,there are differences in the microstructure and properties of SLMed samples in different construction angles.So this study uses 316 L stainless steel and AlSi10 Mg alloy prepared by SLM with 0-90° construction angles.And analyze the effects of microstructure,mechanical properties and heat treatment in different construction angles.The main conclusions are as follows:(1)SLMed 316 L stainless steel with construction angles from 0° to 90°,the lapped tracks had deflection with the construction angle increasing,and the grain size of the 60° sample was the smallest.With the increasing of construction angles from 0° to 90°,the microhardness tended to increase first,and then decrease,while then increase and decrease.The tensile strength and yield strength showed an increasing and then decreasing trend,while the elongation rate decreases gradually,the 60° sample showed good comprehensive mechanical properties,and its microhardness,tensile strength,yield strength and elongation reached 275 HV,720.49 MPa,600.48 MPa and 54.51%.After heat treatment,the grain growth degree of 45° and 90° samples was significant;the microhardness increases first and then decreases with the deflection of construction angles from 0° ?45°?60° to 90°.The maximum of hardness of 60° sample was 190.46HV;the tensile strength and yield strength tended to increase first and then decrease,and the elongation rate increased gradually.After heat treatment,the mechanical properties of 45° sample are the best and its tensile strength,yield strength and elongation was 640.03 MPa,405.96 MPa and 80.51%.(2)The change trend of the lapped tracks of AlSi10 Mg alloy prepared by SLM in construction angles from 0° to 90° was the same as that of 316 L stainless steel.The grains of 45° sample were the smallest and well-distributed,and its microhardness reached a maximum of 154.44 HV.With the deflection of construction angles from 0° to 90°,the tensile strength and elongation tended to increase first and then decrease,and the yield strength gradually decreased.Due to the smallest grains and well-distributed characterization of fracture surface,the 60° sample showed a good combination of tensile strength,yield strength and elongation,which were 476.09 MPa,298.30 MPa and 9.25%.After heat treatment,the lapped tracks of AlSi10 Mg alloy was similar to the previous ones.The Si phase in the heat affected zone breaked and spreaded to the area where the grains were smaller.With the deflection of construction angles from 0° ?45°?60° to 90°,the microhardness showed a trend of increasing first and then decreasing,45° sample showed a maximum microhardness of 130.84HV;the tensile strength showed a trend of increasing first and then decreasing,and the yield strength and elongation gradually decreased,and the 60° sample showed a good combination of tensile strength,yield strength and elongation,which were 320.86MPa?160.13 MPa? 10.77%.