Tensile response at low strains and damping capacity were characterized in pure magnesium and Mg 1 massCa alloy with the aim of revealing the effect of extrusion process and Ca addition. The damping capacity of extruded magnesium and solution treated Mg 1 massCa alloy was lower than that of cast magnesium in the strain range examined. The proportional limit in the stress strain relation of extruded magnesium and solution treated Mg 1 massCa alloy was higher than that of cast magnesium. For all materials examined, the proportional limit corresponded to the critical strain, above which damping capacity begins to increase with strain. This suggests that dislocations breaking away from weak pinning points such as impurity/solute atoms causes the deviation from linearity in the stress strain relation.
Friction stir processing of a thermally sprayed WC-CrC-Ni cemented carbide layer was carried out to clarify the optimum conditions for obtaining a hardened layer without any cracks and pores. Although cracks and pores were observed in the cemented carbide layer after friction stir processing at a forging load of 4.9 kN, friction stir processing at a higher forging load of 9.8 kN or 14.7 kN could eliminate these defects. The amount of pores was decreased owing to rearrangement of WC particles by the stirring effect. The cracks were suppressed by densification of the cemented carbide layer and the martensitic transformation of the SKD61 substrate during cooling. When the forging load was 14.7 kN, the hardness of the cemented carbide layer reached to 2200 HV. On the other hand, friction stir processing at 19.6 kN caused large plastic deformation of the SKD61 substrate and cracks occurred in the cemented carbide layer on the advancing side.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.