Comparative analysis of microstructure,mechanical,and corrosion properties of biodegradable Mg-3Y alloy prepared by selective laser melting and spark plasma sintering

This work explored possibilities of biodegradable magnesium alloy Mg-3Y preparation by two modern powder metallurgy techniques–spark plasma sintering(SPS)and selective laser melting(SLM).The powder material was consolidated by both methods utilising optimised parameters,which led to very low porosity(∼0.3%)in the SLM material and unmeasurably low porosity in the SPS material.The main aim of the study was the thorough microstructure characterisation and interrelation between the microstructure and the functional properties,such as mechanical strength,deformability,and corrosion resistance.Both materials showed comparable strength of∼110 MPa in tension and compression and relatively good deformability of∼9%and∼21%for the SLM and SPS materials,respectively.The corrosion resistance of the SPS material in 0.1 M NaCl solution was superior to the SLM one and comparable to the conventional extruded material.The digital image correlation during loading and the cross-section analysis of the corrosion layers revealed that the residual porosity and large strained grains have the dominant negative effect on the functional properties of the SLM material.On the other hand,one of the primary outcomes of this study is that the SPS consolidation method is very effective in the preparation of the W3 biodegradable alloy,resulting in material with convenient mechanical and degradation properties that might find practical applications.

The slip activity during the transition from elastic to plastic tensile deformation of the Mg-Al-Mn sheet

The deformation behavior of the Mg-Al-Mn sheet was investigated during tensile loading along the rolling(RD)and transversal direction(TD)with special attention to the early stage of deformation.The activity of dislocation slip systems during the transition from elastic to plastic deformation was revealed by the acoustic emission(AE)technique.The parametrization and statistical AE analysis using the adaptive sequential k-mean(ASK)clustering provided necessary information about the individual deformation mechanisms and their evolution.The AE findings were supported by microstructural analyses,including in-situ secondary electron(SE)imaging and Schmid factor estimation for the activity of particular dislocation slip systems with respect to the loading direction.It was found that basal slip is the dominating mechanism up to the stress of~80 MPa in both loading directions with an absolute dominance during the RD-loading,while during the TD-loading,the contribution of prismatic slip to the deformation at stresses above 50 MPa was determined.Below the yielding in both loading directions,the predominance of prismatic over pyramidal slip was found at the stress in the range of 80-110 MPa and the opposite tendency occurred at stresses between 110 and 140 MPa.