Bulk metallic glasses (BMGs) are excellent alloys in strength, fatigue strength, fracture toughness and corrosion resistance. Therefore, the BMGs are attractive for machine and structural members. However the shear and torsional properties were not known enough. Then, we conducted the torsional tests in the BMG, and investigated the fracture and fatigue characteristics. Test Zr-based bulk
... [Show full abstract] metallic glass prepared by arc melting tilt casting method consisted of Zr55Cu30Al10Ni5 at.%. Shear stress-shear strain diagrams showed elastic-perfectly plastic deformation with large plastic strain and many shear bands in maximum shear stress directions, regardless of the differences between the test specimen diameters, lengths, magnitude of Rs at the end of parallel part. The fatigue limit in torsional fatigue test τW and fatigue ratio τW/τB (τB = torsional strength ) were 650 MPa and 0.59, respectively. The fatigue crack initiated at the specimen surface in the maximum shear stress direction and propagated in the normal direction for the maximum tensile stress with striation like patterns.
