In the present study, the effect of grain size on the austenite stability was studied by nanoindentation tests in a 304L stainless steel. Thermomechanical processing based on cold rolling and annealing was used to produce two different types of austenite: ultrafine grained (UFG) austenite with the average grain size of 0.65 μm and coarse grained (CG) austenite with the average grain size of 12 ...

Aluminum is one of the most abundant lightweight metals on Earth with broad practical applications, such as in electrical wires. Although traditional aluminum manufacturing by alloying, deformation and thermomechanical means addresses balance between high strength conductivity, adding metallic ceramic nanoparticles into matrix can be an exciting alternative approach to mass produce Here, we sho...

In the present work, new possibilities of the X-ray diffraction for investigations of the 17 phase composition, size, shape and volume fraction of particles in ultrafine-grained (UFG) 18 martensitic steel and the Cu-Cr-Zr alloy have been demonstrated. For the first time, the method of 19 X-ray diffraction in the transmission mode was used to identify particles with a volume fraction of 20 less ...

The processing of metals through the application of severe plastic deformation (SPD) techniques provides the potential for achieving exceptional grain refinement leading to ultrafine-grained (UFG) materials in bulk solids. These materials generally exhibit high strength but very limited ductility at room temperature (RT) leading to the so-called paradox of strength and ductility. The recent dev...

Recently, machining has been exploited as a means for producing ultra-fine grained (UFG) and nanocrystalline microstructures for various metal materials, such as aluminum alloys, copper, stainless steel, titanium and nickel-based super alloys, etc. However, no predictive, analytical or numerical work has ever been presented to quantitatively predict the change of grain sizes during machining. I...

Abstract: nanocrystalline nickel samples with the grain size of ~25 nm were prepared via direct current electrodeposition andaluminized for different durations by pack cementation method at 500 means of SEM, EDS and XRD techniques. According to results, short time aluminizing resulted in the formation of asingle aluminide layer whereas at long duration two distinct aluminide layers were formed....

In the present study, an ultrafine grained (UFG) 304L stainless steel with the average grain size of 300 nm was produced by a combination of cold rolling and annealing. Weldability of the UFG sample was studied by Nd: YAG laser welding under different welding conditions. Taguchi experimental design was used to optimize the effect of frequency, welding time, laser current and laser pulse duratio...

Nanoindentation morphologies of crystalline copper have been probed at the grain scale. Experimental tests have been conducted on nanocrystalline (NC), ultrafine-grained (UFG), and coarse-grained (CG) copper samples with a new Berkvoich indenter at the strain rate of 0.04/s without holding time at an indentation depth of 2000 nm at room temperature. As the grain size increases, the height of th...

Equal channel angular rolling (ECAR) process is one of the severe plastic deformation (SPD) methods that have been used to make ultra-fine grain (UFG) materials with improving the mechanical properties of samples. After performing the process at several paths, a large strain is applied to the material that can cause decreasing the grain size and improving the mechanical and physical properties ...

We present the results of in-situ studies of evolution of grain boundary misorientations in ultrafine grained (UFG) aluminum alloy Al-4 Cu-0.5 Zr (wt%) during annealing. The structure of the UFG alloy was obtained by severe plastic deformation method. Misorientations between the grains were measured using single reflection technique. It was found that relaxation processes during annealing are a...