Compressive strengths of molybdenum alloy micro-pillars prepared using a new technique

From “Smaller is Stronger” to “Size‐Independent Strength Plateau”: Towards Measuring the Ideal Strength of Iron

“…GPa [16], about 11% lower than that of pure Mo. Nevertheless,  is only ～0.038G, about 3 times lower than the ideal shear strength predicted by theoretical calculations [17].…”

A new regime for mechanical annealing and strong sample-size strengthening in body centred cubic molybdenum

“…2d) after mechanical annealing looks rather like the pristine Mo achieved by high-temperature formation or annealing 4,12 , in the sense of lacking 'obvious' dislocation lines ('obvious' defined here by the contour length of a dislocation being a significant fraction of D) or dislocation forest inside. But one cannot tell whether some point defects or tiny point-defect clusters still remain in the cleaned region, as they are beyond the resolution of conventional TEM.…”

“…T he deformation behaviour of small-volume metals, in particular the effects of sample size (that is, the diameter D of micro-and nano-pillars) on the apparent strength σ, has been attracting considerable attention recently [1][2][3][4][5][6][7] . A number of studies of single-crystal micro-and nano-pillars have demonstrated the 'smaller is stronger' trend, with the flow stress increasing markedly with decreasing sample size.…”

“…Particularly interesting are the behaviours of BCC metals, which in bulk form tend to exhibit significant deviations from FCC metals. Molybdenum (Mo) is a representative and widely studied example [3][4][5][6][12][13][14] of such BCC metals.…”

“…First, investigations so far indicate BCC Mo pillars exhibit a relatively weak sample-size dependence at room temperature 3,15,16 . In an extreme case of Mo-alloy pillars produced by high-temperature eutectic solidification followed by chemical etching, the samples were believed to be initially dislocation free, and the flow stress was reported to be independent of the pillar size 4,17 . In focused ion beam (FIB) micro-machined pillars, α was found to be < ~0.45 for Mo by several groups 3,15,16 , considerably lower than those for FIBed FCC metallic pillars.…”