Deformation-induced grain-growth in nanocrystalline materials is a widely-reported phenomenon that has been attributed to grain boundary (GB) processes. In this paper, we report on the opposite phenomenon, wherein stable (NC) Cu-Ta alloy undergoes further refinement of nano-grains during severe plastic deformation (SPD). SPD up 250% results significant grain-size reduction despite 350°C increas...

High strength aluminum alloys, especially those containing zirconium, are historically difficult to grain refine. Early efforts by Alcoa indicated that the addition of lithium to these alloys increases difficulty with grain refinement. Although grain refining of alloys 2090 and 2091 was possible, consistent results were not obtained. Statistically-designed experiments were used to quickly ident...

Formation of nano/ultrafine grain structure in AISI 304L austenitic stainless steel through the martensite reversion treatment was studied. The solution annealed specimens were cold rolled up to 95 % thickness reduction at -15°C. The cold-rolled specimens were subjected to reversion annealing treatment at the temperature range of 700-1000 °C for 10–150 min. Microstructural evolutions were analy...

The evolution of microstructure and mechanical properties of a magnesium cast alloy (AZ31) processed by equal channel angular pressing (ECAP) at two different temperatures were investigated. The as-cast alloy with an average grain size of 360  was significantly refined to about 5  after four ECAP passes at 543 K. Grain refinement was achieved through dynamic recrystallization (DRX) du...

Rapid dendrite growth in single- or dual-phase multicomponent alloys can be manipulated to improve the mechanical properties of such metallic materials. Rapid growth of (αFe) dendrites was realized in an undercooled Fe-5Ni-5Mo-5Ge-5Co (wt.%) multinary alloy using the glass fluxing method. The relationship between rapid dendrite growth and the micro-/nano-mechanical properties of the alloy was i...

Magnesium (Mg) has drawn increasing attention as a tissue engineering material. However, there have been very few studies of laser-melted Mg-Zn alloys. In this study, four binary Mg-xZn (x = 2, 4, 6 and 8 wt. %) alloys were fabricated by laser melting. The influence of zinc (Zn) content and technique on the degradation behavior and mechanical properties of Mg were discussed. Results revealed th...

The grain size refinement of AISI 422 martensitic stainless steel in the temperature range of 950-1150 ºC was investigated by hot deformation tests. The deformed specimens were held at deformation temperature with delay times of 5 to 300s after achieving a strain of 0.3. The austenite grains exhibit a considerable growth at temperature higher than 1050˚C, while the grain coarsening is negligibl...

Friction stir processing (FSP) has been developed on the principles of friction stir welding (FSW) as an effective and efficien new method for grain refinement and microstructural modification, providing intense plastic deformation as well as higher strain rates than other conventional severe plastic deformation methods. FSP produces an equiaxed homogeneous microstructure consisting of fine gra...