Room temperature grain boundary sliding behavior of fine-grained Mg-Mn alloys

Deformation modes during room temperature tension of fine-grained pure magnesium

“…lean alloy) Mg alloys. The enhancement in ductility and formability made by this approach is so significant that samples exhibit a total elongation of more than 100% or nearly infinite compressive formability [16][17][18][19][20][21][22][23]. These findings provide a new approach for designing and developing highly formable products from Mg and its dilute alloys.…”

“…In the case of highly ductile Mg (> 100%) at room temperature as reported in Refs. [18][19][20][21][22], however, grains are microcrystalline rather than nanocrystalline, and the deformation temperature is only 0.32T m of Mg (Mg T m = 923K (650 C)), which is considerably below 0.5T m . Although trace of GBS has been observed on the surface of fine-grained Mg after tensile deformation at 0.32T m [18][19][20][21][22], clarifying how GBS operates as a dominant deformation mode at such a (relatively) low temperature inside bulk microcrystalline Mg presently remains an open question.…”

“…[18][19][20][21][22], however, grains are microcrystalline rather than nanocrystalline, and the deformation temperature is only 0.32T m of Mg (Mg T m = 923K (650 C)), which is considerably below 0.5T m . Although trace of GBS has been observed on the surface of fine-grained Mg after tensile deformation at 0.32T m [18][19][20][21][22], clarifying how GBS operates as a dominant deformation mode at such a (relatively) low temperature inside bulk microcrystalline Mg presently remains an open question. Moreover, the important evidence that supports the operation of GBS in the cited studies [18][19][20][21][22] is that the ductility is sensitive to strain rate, and the strain rate sensitivity values (m) are around 0.2-0.3.…”

“…Although trace of GBS has been observed on the surface of fine-grained Mg after tensile deformation at 0.32T m [18][19][20][21][22], clarifying how GBS operates as a dominant deformation mode at such a (relatively) low temperature inside bulk microcrystalline Mg presently remains an open question. Moreover, the important evidence that supports the operation of GBS in the cited studies [18][19][20][21][22] is that the ductility is sensitive to strain rate, and the strain rate sensitivity values (m) are around 0.2-0.3. Empirically, plastic deformation by GBS is characterised by a m-value of ~0.5, whilst m = 0.2-0.3 corresponds to deformation dominated by dislocation-controlled creep, rather than GBS [35,36].…”

“…These findings provide a new approach for designing and developing highly formable products from Mg and its dilute alloys. Existing studies [18][19][20][21][22] proposed that the high ductility at room temperature is achieved by the occurrence of grain boundary sliding (GBS).…”