Mechanical and tribological properties of Zr-based bulk metallic glass for sports applications

Abstract

The microstructure, and mechanical and tribological properties of zirconium-based bulk metallic glass (Zr-BMG) were investigated for golf club heads. The Zr-BMG had a fully amorphous structure without any detectable crystalline phases. The hardness and Young's modulus of the Zr-BMG were relatively high even though they were lowered by about 36% and 28% respectively by the increased indentation depth from 200 to 1000nm due to strain softening during the nanoindentation test. The tribological behaviour of the Zr-BMG was investigated by sliding against alumina (Al2O3), 100Cr6 steel or polymethyl-methacrylate (PMMA) balls under normal loads of 1–3N. The wear of the Zr-BMG tested against the Al2O3 and 100Cr6 balls became higher with higher normal loads while a higher wear resistance of the Al2O3 ball than that of the 100Cr6 ball caused a higher wear of the Zr-BMG. A much lower wear resistance of the PMMA ball than that of the Zr-BMG resulted in a preferential wear of the PMMA ball without generating any apparent wear of the Zr-BMG during the testing. The Zr-BMG tested against the Al2O3 ball exhibited the highest wear under all the normal loads due to the highest wear resistance of the Al2O3 ball among the counter balls.