»ã±¨±êÌâ (Title)£ºProbing small-scale fracture and plasticity in quasicrystals and high-entropy alloys£¨×¼¾§ºÍ¸ßìغϽðµÄÓ׳߶ȶÏÁÑÓëËÜÐԵļì²â£©

»ã±¨ÈË (Speaker)£º×ÞÓî ½ÌÊÚ£¨¶àÂ׶à´óѧ£©

»ã±¨¹¦·ò (Time)£º2021Äê11ÔÂ19ÈÕ(ÖÜÎå) 10:00

»ã±¨µØÖ· (Place)£ºÏßÉÏZoom:

»áÒé ID£ºJoin Zoom Meeting

https://utoronto.zoom.us/j/2822310747?pwd=SjU2dUpEMXZTWGkxTHRsTWJwZnlRZz09

Meeting ID: 282 231 0747

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Ô¼ÇëÈË(Inviter)£ºÀîÓÀÀÖ ¸±½ÌÊÚ

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ÌáÒª£ºIn the first part of the presentation, we show that typically brittle quasicrystals can exhibit remarkable ductility of over 50% strains and high strengths of ¡«4.5?GPa at room temperature and sub-micrometer scales. In contrast to the generally accepted dominant deformation mechanism in quasicrystals¡ªdislocation climb, our observation suggests that dislocation glide may govern plasticity under high-stress and low-temperature conditions. The ability to plastically deform quasicrystals at room temperature should lead to an improved understanding of their deformation and fracture mechanism.

In the second part of the presentation, we present that the fracture properties of high-entropy alloys (HEAs). Most refractory high-entropy alloys (HEAs) are brittle and suffer from limited formability at ambient temperature. Here, using in situ micro-cantilever tests, we show that the fracture toughness of a bi-crystal HEA, Nb25Mo25Ta25W25, is one order of magnitude lower than that of single crystalline ones. In addition, we have documented and described aspects of mud-cracking specific to Cr-containing electrodeposited HEA alloys made from trivalent Cr electrolytes.