Influence of cold-rolling reduction on retained austenite texture in cold-rolled and intercritically annealed TRIP-assisted steel

The newly developed multiphase transformation-induced plasticity (TRIP) steels are of interest for industrial applications because of their excellent combination of high strength and ductility. Their performance can be successfully controlled by designing an optimum balance in the volume fractions of ferrite, bainite and retained austenite. The characteristics of the retained austenite are considered to be the main key to achieving the desired final properties. Against this background, the effects of retained austenite characteristics, such as volume fraction, carbon concentration, size and shape, on the behaviour of TRIP steels have been studied. The crystallographic orientation of the retained austenite was measured by electron backscattered diffraction (EBSD). The effect of initial cold-rolling reduction on the microtexture development of the retained austenite was studied on an aluminium-containing TRIP steel. The results show that, by increasing the cold-rolling reduction before the final austempering, the main components of the face-centred cubic phase, i.e. copper, brass and Goss, dominate the texture of the retained austenite. In contrast, the copper and Goss components of the retained austenite are absent in the texture of lightly deformed sheets. The features of the preferred orientation of the retained austenite are discussed and explained in terms of the annealing texture of the recrystallized ferrite and bainite

Deformation behavior and processing map of ATI 425 with initial lamellar microstructure

The effect of hot compression temperatures and strain rates on deformation behavior and resultant microstructure of ATI 425 alloy with initial lamellar microstructure was investigated in this study. The temperature and strain rate of the hot compression test were chosen to be in the 700-1100 °C and 0.001-1 s-1 ranges, respectively. The stress-strain curve and microstructure evaluation show that the alloy's flow softening is associated with globularization and dynamic recrystallization mechanisms. The constitutive equation calculates the activation energy for the α/β and β regions to be 348 kJ/mol and 201 kJ/mol, respectively. Dynamic recovery and partial recrystallization are the dominant structure modification mechanisms in the beta single-phase region. Bending and fragmentation of alpha plates is the dominant mechanism of microstructure promotion in the α/β region at low temperatures and low strain rates, less than 0.1s-1. Local shear and alpha plate break-up are the main factors in structural modification at high strain rates, greater than 0.1s-1. The extracted process map at 0.5 strain revealed three zones: instability, safe zone, and peak zone, with power dissipation efficiencies of 0 -0.25%, 30-40%, and above 40%

Evaluation of Mechanical Properties and Structure of 1100-Al Reinforced with Zro2 Nano-particles via Accumulatively Roll-bonded

AbstractIn this study, aluminium metal composites reinforced with Zirconium dioxide (ZrO2) nano-particles in different of volume percentage are manufactured through accumulative roll bonding. The results indicate that with the application of 10 ARB cycles and the composite microstructure shows excellent ZrO2 particle distribution in the Al matrices. The X-ray diffraction results also showed that nanostructured Al/ZrO2 Nanocomposite with the average crystallite size of 48.6nm was successfully achieved by employing 10 cycles of ARB process. According to the results of this study, the tensile, hardness, and elongation properties of the Al/ZrO2 composite are determined for 0.50, 0.75 and 1 vol.% ZrO2