Twinning is a major mechanism of plastic deformation in hexagonal close-packed (hcp) structures. However, mechanistic understanding twin nucleation and growth has yet to be established. This paper reviews the recent progress twinning hcp materials—particularly newly discovered phase transformation-mediated mechanisms—in terms crystallographical analysis, theoretical mechanics calculations, nume...

The high hardness or yield strength of an alloy is known to benefit from the presence of small-scale precipitation, whose hardening effect is extensively applied in various engineering materials. Stability of the precipitates is of critical importance in maintaining the high performance of a material under mechanical loading. The long period stacking ordered (LPSO) structures play an important ...

The ZK61 alloy rods with different grain sizes and crystallographic texture were successfully fabricated by cyclic extrusion and compression (CEC). Their room-temperature tension & compression yield strength displayed a significant dependence on grain size and texture, essentially attributed to {10-12} twinning. The texture variations were characterized by the angle θ between the c-axis of ...

The plastic co-deformation behavior at the homophase interfaces between the hard nanotwinned grain inclusions and the soft recrystallized matrix grains in a duplex-microstructured AISI 316L austenitic stainless steel is examined through the analysis of long-range orientation gradients within the matrix grains by electron backscatter diffraction and transmission electron microcopy. Our analysis ...

We present a surface stacking fault (SSF) energy approach to predicting defect nucleation from the surfaces of surface-dominated nanostructure such as FCC metal nanowires. The approach leads to a criterion that predicts the initial yield mechanism via either slip or twinning depending on whether the unstable twinning energy or unstable slip energy is smaller as determined from the resulting SSF...

A dual phase Ti-6A1-4V alloy was tested in uniaxial tension over a large quasi-static loading range (10−5–10−1 s−1) in ambient environment. As strain rate increases, strength of the alloy was found to increase at the expense of ductility. In the low strain-rate region, strain rate sensitivity of the material experienced a gradual decrease during plastic deformation. In the high strain-rate regi...