Experimental and modelling characterisation of residual stresses in cylindrical samples of rapidly cooled bulk metallic glass

• A new analytical model of thermal diffusion and deformation during tempering is presented
• Residual stresses in a Zr-based bulk metallic glass cylinder were mapped by Focused Ion Beam–Digital Image Correlation
• The two methods show good agreement, confirming that both approaches can be used widely for a range of problems

Quench processing is widely used in industry to impart the desired structural and mechanical properties by controlling microstructure and compositional gradients, e.g. to obtain supersaturated solid solutions in aluminium alloys, or to achieve martensitic hardening in steels. Rapid cooling, also referred to as quenching or tempering, is also the principal production route for bulk metallic glasses that exhibit high hardness and strength due to their amorphous structure that precludes plastic deformation by easy crystal slip. Importantly, rapid cooling is accompanied by the creation of residual stresses that also have a strong effect on the deformation behaviour.The present study aims to obtain insight into the residual stresses in cylindrical samples of Zr-based bulk metallic glass (BMG) by combining analytical modelling of thermal and mechanical problems with experimental measurements using Focused Ion Beam–Digital Image Correlation (FIB-DIC) ring-core milling. The results show good agreement between the two approaches, providing improved confidence in the validity of the two approaches considered here.

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