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Lecture

WEB Linking structure to fracture through small-scale mechanical analyses of a laser-processed bulk metallic glass

Wednesday (01.01.2020)
04:30 - 04:45
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The recent development of laser powder bed fusion (LPBF) of bulk metallic glasses (BMGs) opens up the possibility of creating large BMG components with complex geometries. However, additive manufactured BMGs exhibit poor ductility and toughness when compared to their traditionally as-cast counterparts. In this work, we show how small-scale mechanical measurements can help to understand and rationalise structural differences between LPBF and cast Zr-based BMGs, through variability in their mechanical response. The LPBF-processed alloy showed significantly lower fracture toughness when compared with the as-cast alloy, and this was explained by energetic barriers for activating shear transformations in the glass, elucidated in detail using micro-pillar compression testing. Evaluation at the micro-scale is critical, as thermal influences on the microstructure from laser-processing and melt-pool solidification exist at these length-scales. These results are further related to the glassy laser-processed structure through advanced structural analyses using synchrotron X-ray diffraction and nanoindentation. Our results show that micro- and nano-mechanical measurement is an effective tool for understanding material deformation of laser-processed amorphous alloys at critical length scales.

Speaker:
Dr. James Best
Max-Planck-Institut für Eisenforschung GmbH