Residual stresses in bulk metallic glasses - II: Measurement

New multi-component metallic alloys with exceptional glass forming ability have recently been developed at Caltech. These alloys allow the processing of large amorphous specimens. The possibility of formation of thermal-tempering-induced residual stresses during the processing of these bulk metallic glass (BMG) specimens was investigated. The crack compliance method was used to measure the stress profiles in a BMG plate that was cast in a copper mold. The measured profiles were roughly parabolic suggesting that thermal tempering was the dominant residual stress generation mechanism. However, the magnitude of the measured stresses was significantly lower than modeling predictions. Possible reasons for this discrepancy are presented in relation to the actual casting process and material properties.