Strength and fracture mechanism of a magnesium alloy for medical applications after equal-channel angular pressing

Abstract

In this paper, we study the strength and fracture mechanism of the cast magnesium alloy Mg-Zn-Ca (1.0 % Zn, 0.2 % Ca) for medical applications after equal-channel angular pressing (ECAP) in comparison with the initial condition (after homogenization annealing). Mechanical tests included tensile and torsion tests of samples with a diameter of 3 mm and impact strength tests of samples with a V-shaped stress raiser. The microrelief of all fractures was studied in a Phenom ProX G6 scanning electron microscope (SEM). The results of tensile testing of the samples showed that the strength of the alloy after ECAP increased by a factor of 1.5 –1.8, and the elongation increased by a factor 2.6. The torsional strength of the alloy increased by a factor 1.1–1.3, and the relative shear of the alloy decreased by factor a 1.3 as compared with the alloy after annealing. In contrast to static loads, the magnesium alloy Mg-Zn-Са after ECAP is poorly resisting one-time impact loads. Analysis of the results of this study allows us to conclude that the magnesium alloy Mg-Zn-Ca after ECAP is more promising for the manufacture of medical products that experience static loads during operation, as compared with the alloy after annealing.