[en] Austenite stainless steels with stable and metastable austenite phase were studied for the evolution of texture during cold rolling. After solution annealing treatment AISI 304L and 316L austenitic stainless steels (ASS) were unidirectionally cold rolled to different degrees of thickness reductions up to 90% of cold reduction. Texture measurements were made at the surface as well as at the mid-plane sections by X-ray diffraction technique. Distinctly two different types of textures were noted at the surface and mid-plane section. The surface texture showed texture transition from copper type to Brass type whereas the mid-plane section showed typical Brass type texture from the very beginning of deformation

[en] Polycrystalline alumina and stainless steel were brazed at 900, 1000 and 1100 deg. C. Microstructural and mechanical property of the interface have been correlated. Interface was characterized by scanning electron microscopy and transmission electron microscopy. SS interface consists of FeTi and Fe₃₅Cr₁₃Ni₃Ti₇ phase whereas TiO, Al₂TiO₅ and Cu₃Ti₃O phases have been found at the Al₂O₃ interface. Shear strength of the joints was evaluated for different samples and maximum strength of 94 MPa has been obtained. Residual stress produced due to the coefficient of thermal expansion mismatch between the substrate and the reaction products at the interface, has been measured by X-ray diffraction technique. Thickness of the interface and the microstructural arrangements of the different reaction products at the interface play a vital role in determining the mechanical property of the joint. Optimum process parameters have been determined

[en] 6063 Al alloy is subjected to severe plastic deformation through high-pressure torsion (HPT) using disk samples. The values of the Vickers microhardness and equivalent strain were recorded along diameters in each disk. The microhardness of 6063 Al alloys increases strongly and continuously with increasing equivalent strain but levels off and enters into a steady-state where the hardness remains unchanged with further straining. It is confirmed that the yield and ultimate tensile strength also follows the same single role of the equivalent strain as the hardness. Transmission electron microscopy showed that a subgrain structure develops at an initial stage of straining with individual grains containing dislocations. When increasing the straining, the subgrain size decreases whereas the misorientation angle increases and more dislocations are formed within the grains. In the steady-state range, some recrystallized grains formed which are free from dislocations. The mechanism for the grain refinement is discussed in terms of dislocation mobility.

[en] The strain-hardening behavior of Al-1 wt.% Sc alloy was studied and compared with that of Al. Al showed a linear hardening, whereas the Al-1 wt.% Sc alloy showed two-stage behavior for the same equivalent true strain up to 2.0. Transmission electron microscopy studies revealed that dislocation pile-up and dynamic recovery control the hardening behavior in Al, whereas the effective pinning by fine Al₃Sc precipitates and dynamic recrystallization at large strain are responsible for the two-stage behavior in Al-1 wt.% Sc alloy

[en] Low-carbon microalloyed steel was subjected to warm rolling followed by rapid transformation annealing (RTA) at 800-850 °C and subcritical annealing (SCA) at 600 °C to develop ultrafine ferrite grain structures (UFFG) with grain size less than 3 μm. The present study investigated the influence of light (40%) and heavy (80%) warm rolling deformation (LWR and HWR) applied during the finishing pass of two-pass rolling schedules on the microstructural evolution after rolling and subsequent annealing treatments. RTA treatment of HWR sample at a lower intercritical temperature for an optimum duration (800 °C, 30 s) developed UFFG-martensite dual-phase structure that offered the best combination of strength (YS ~ 900 MPa and UTS ~ 1200 MPa) and ductility (25% elongation). The SCA treatment provided sufficient time to achieve a uniform distribution of carbide particles throughout the ferrite matrix. SCA treatment of HWR at 600 °C for 4 h developed UFFG-carbide structure achieving YS of 800 MPa with 20% ductility. The SCA of LWR resulted in coarser ferrite grain structures (grain size > 5 μm) having higher ductility (more than 30%) but lower strength (UTS of 400-550 MPa) as compared to RTA.