High specific strength of the material is critical for many structural applications in automotive and aerospace design. Among many other approaches for strengthening the materials, development of superfine and nano grained microstructure is becoming popular. Different techniques for producing ultra-fine-grained (UFG) materials have been introduced especially in the last decade. The advantages o...

In this paper, an ultra low carbon High Strength Low Alloy Grade Steel was subjected to a two-step forging process and this was followed by different post cooling methods. The highest strength was obtained at a faster cooling rate due to the highly dislocated acicular ferrite structure with the fine precipitation of microalloying carbides and carbonitrides. At a slow cooling rate, the strength ...

The cross-rolling is a new process that results in significant evolutions in microstructure of the metallic sheets. In this study, an aluminium 1050 sheet was rolled up to 95% reduction in cross directions for ten passes. The rolled samples were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The rolled samples possess a high dislocation density and ultra-fin...

The influence of Mo alloying on the thermal stability of grain size, dislocation density and hardness of ultrafine-grained (UFG) Ni alloys was studied. The UFG microstructure in alloys with low (∼0.3 at.%) and high (∼5 at.%) Mo contents was achieved by high-pressure torsion (HPT) performed for 20 turns at room temperature. The thermal stability of the two alloys was studied by calorimetry. A Cu...

Two different aspects of the thermal stability of grains were studied – (i) thermal stability of grain structure evolution during friction stir processing (FSP), and (ii) thermal stability of grains after FSP. It was concluded that Al3(Sc,Zr) dispersoids are effective in limiting grain growth to ultrafine grained regime (UFG) by stabilizing the microstructure during FSP. The presence of these d...

Equal channel angular pressing (ECAP) is one of the most prominent procedures for achieving ultra-fine grain (UFG) structures among the various severe plastic deformation (SPD) techniques. In this study, the effect of ultrasonic vibration on deformation behavior of commercial pure aluminum in the ECAP process is analyzed successfully using three dimensional (3D) by finite element methods (FEMs)...

in the present study, the effect of grain size on the austenite stability was studied by nanoindentationtests in a 304l stainless steel. thermomechanical processing based on cold rolling and annealing wasused to produce two different types of austenite: ultrafine grained (ufg) austenite with the averagegrain size of 0.65 μm and coarse grained (cg) austenite with the average grain size of 12 μm....

Commercially pure nickel was processed by equal channel angular pressing (ECAP) through route Bc for 12 passes to obtain an ultrafine grained (UFG) microstructure and further subjected to an ultrasonic treatment (UST) which introduced a maximum amplitude equivalent to anormal stresses of 100 MPa in a steady state regime. It was observed that the microstructure of UFG Ni can be differently alter...