Mechanical and Fatigue Behavior of Ca₆₅Mg₁₅Zn₂₀Bulk-Metallic Glass

A number of BMGs, such as Zr-, Fe-, Pd-, Al-,and Ni-based alloys, have been discovered after the rapid development of glass-forming alloys during the early 1990s.([1 4]) Ca-Mg-Cu and Ca-Mg-Cu-Ag BMGs were successfully fabricated by Amiya and Inoue in 2002.([5,6]) Following these reports, numerous Ca-based BMG systems have been produced and studied.([5 21]) Ca-based BMG alloys are of interest because of their unique properties, such as low density (similar to 2.0 g cc (1)), low Young's modulus (similar to 17-20 GPa) that is comparable to the modulus of human bones, low glass-transition temperature (T-g similar to 100 degrees C) and a wide super-cooled liquid temperature range (Delta T-xg T-x - T-g approximate to 30-80 C).([15,18]) Elements such as Ca, Mg, and Zn are biocompatible, which makes the Ca-Mg-Zn-based alloys attractive for use in biomedical applications.([18]) The amorphous structure gives unique properties to BMGs, including high elastic strain, high fracture strength, and high fatigue resistance. Although the mechanical behavior of BMGs is studied widely, ([1-4,22,23]) there is no fatigue data for Ca-based BMGs. A comprehensive understanding based on the compression, hardness, and fatigue behavior is critically important for the application of the Ca-based BMGs. In the current paper, the compression behavior, Vickers hardness, and fatigue characteristics of Ca65Mg15Zn20 BMGs were investigated at room temperature in air. A mechanistic understanding of the fatigue and fracture mechanisms of Ca-based BMGs is proposed.