Corrosion Bending Fatigue of RESOLOY^® and WE43 Magnesium Alloy Wires

RESOLOY^®, a magnesium resorbable alloy based on Mg–Dy is the focus of this study. Corrosion bending fatigue behavior of RESOLOY wires was investigated with WE43 serving as a reference. Since these wires are developed for absorbable implant applications like stents, clips and anastomotic nails, circulating Ringer solution of 37 °C was used to simulate body conditions. The alloys were first extruded and finally cold-drawn to a wire diameter of 500 µm. Both alloys show very fine grains. The microstructure of WE43 was found homogeneous and equiaxed. RESOLOY shows recrystallized but non-equiaxed grains. RESOLOY is slightly harder than WE43. Both alloys were subjected to strain-controlled fatigue and corrosion fatigue in a sequence which mimicked stent crimping, expansion, and in-vessel cycling. Fatigue life was strongly influenced by corrosion. Fatigue data for RESOLOY highlight the need for further wire processing optimization work that is currently underway.