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Through ex situ and in situ compression and tension tests of micrometer- and submicrometer-sized single crystal hexagonal close packed (HCP) Ti alloy pillars oriented for prismatic slip, we have observed that 'smaller is stronger' and the larger samples exhibit obvious strain bursts. However, for extremely small samples, the plastic flow becomes much more stable both in compression and tension, mainly due to the emergence of a high density of basal stacking faults (SFs) driven by extremely high stress, which rarely appear in larger samples and bulk counterpart. This work demonstrates a recipe towards ultra-high strength (GPa level) nanoscale samples with continous plastic flow. [ABSTRACT FROM AUTHOR]

In situ transmission electron microscope compression testing of submicron Al pillars shows two sample size regimes with contrasting behavior underlying the large strain bursts. For small pillars, the bursts originate from explosive and highly correlated dislocation generation, characterized by very high collapse stresses and nearly dislocation-free post-collapse microstructure. For larger pillars, the bursts result from the reconstruction of jammed dislocation configurations, featuring relative low stress levels and retention of dislocation network after bursts. [ABSTRACT FROM AUTHOR]

Strain glass has recently been reported in Ti50-xNi50+x (x≥1.5 at %) alloys and caused by the existence of point defects. This strain glass alloy, being nonmartensitic, exhibits shape memory effect (SME) and superelasticity (SE) around the freezing temperature T0. However, the T0 of Ti50-xNi50+x (x≥1.5 at %) strain glass alloy is very low (∼160 K), thus restricting its potential applications. In the present letter, we report a strain glass system, Ti50(Pd50-xCrx) (x≥9 at %), which has a significantly higher freezing temperature. It is based on a high-temperature martensitic system TiPd (with Ms∼810 K) and dopant Cr (as point defect). For Ti50(Pd40Cr10) strain glass, the freezing transition occurs at T0∼250 K, being close to the room temperature. Correspondingly, it exhibits SME and SE around its high T0. We further clarified that T0 of strain glass alloy is controlled by the martensitic transformation temperature Ms (i.e., martensite stability) of its corresponding host alloy without point defect. Our work provides insight into how to develop strain glass with desired T0 and the associated SME and SE for applications. [ABSTRACT FROM AUTHOR]