Accessing thermoplastic processing windows in metallic glasses using rapid capacitive discharge

作者：Kaltenboeck Georg; Harris Thomas; Sun Kerry; Tran Thomas; Chang Gregory; Schramm Joseph P; Demetriou Marios D^*; Johnson William L

来源：Scientific Reports, 2014, 4(1): 6441.

DOI：10.1038/srep06441

The ability of the rapid-capacitive discharge approach to access optimal viscosity ranges in metallic glasses for thermoplastic processing is explored. Using high-speed thermal imaging, the heating uniformity and stability against crystallization of Zr35Ti30Cu7.5Be27.5 metallic glass heated deeply into the supercooled region is investigated. The method enables homogeneous volumetric heating of bulk samples throughout the entire supercooled liquid region at high rates (similar to 10(5) K/s) sufficient to bypass crystallization throughout. The crystallization onsets at temperatures in the vicinity of the "crystallization nose" were identified and a Time-Temperature-Transformation diagram is constructed, revealing a "critical heating rate" for the metallic glass of similar to 1000 K/s. Thermoplastic process windows in the optimal viscosity range of 10(0)-10(4) Pa.s are identified, being confined between the glass relaxation and the eutectic crystallization transition. Within this process window, near-net forging of a fine precision metallic glass part is demonstrated.

• 出版日期2014-10-1