Showing papers by "Sushanta Kumar Panigrahi published in 2010"
TL;DR: In this paper, the microstructure and texture evolution of cryorolled Al 7075 alloy were investigated using FE-SEM, TEM, and neutron diffraction, respectively.
84 citations
TL;DR: In this paper, an optimized process condition was proposed to achieve both high strength and high ductility in the Al 6063 alloy in order to improve the tensile strength and ductility.
Abstract: High-strength ultrafine-grained (UFG) metals and alloys often show a reduced tensile ductility when compared with their coarse-grained counterparts. The earlier attempts in trying to improve their ductility usually have led to sacrificing its strength. Optimized process conditions are proposed to achieve both high strength and high ductility in the Al 6063 alloy in the current work. It involves solution treatment of the Al 6063 alloy to dissolve the second-phase particles, cryorolling (CR) to produce a high density of dislocations, short annealing (SA) treatment to recrystallize partially the microstructure without affecting the age-hardening effect, and finally aging treatment to generate highly dispersed nano precipitates. The solution treatment prior to CR combined with post-CR SA at 428 K (155 °C) for 5 minutes followed by aging treatment at 398 K (125 °C) for 12 hours are the optimum processing conditions to obtain the UFG microstructure with improved tensile strength (286 MPa) and good tensile ductility (14 pct) in the Al 6063 alloy. It is observed that the accumulation of dislocations and the formation of nanosized precipitates are responsible for improving the strength, whereas both a low dislocation density and a high density of nanosized precipitates contribute to the improvement in ductility of the CR Al 6063 alloy subjected to an optimized treatment of short annealing and aging.
56 citations
TL;DR: In this article, the microstructural evolution and precipitation behavior of cryorolled Al 6063 alloy were investigated, and it was clear from the present study that an ultrafine-grained Al 60 63 alloy exhibits a higher driving force for the precipitation formation when compared to bulk Al alloy.
55 citations
TL;DR: In this article, the effect of annealing on precipitation, microstructural stability, and mechanical properties of cryorolled Al 6063 alloy has been investigated employing hardness measurements, tensile test, XRD, DSC, EBSD, and TEM.
Abstract: The effect of annealing on precipitation, microstructural stability, and mechanical properties of cryorolled Al 6063 alloy has been investigated in the present work employing hardness measurements, tensile test, XRD, DSC, EBSD, and TEM. The solution-treated bulk Al 6063 alloy was subjected to cryorolling to produce ultrafine grain structures and subsequently annealing treatment to investigate its thermal stability. The CR Al 6063 alloys with ultrafine-grained microstructure are thermally stable up to 250 °C as observed in the present work. Within the range of 150–225 °C, the size of small precipitate particles is <1 μm. These small precipitate particles pin the grain boundaries due to Zener drag effect, due to which the grain growth is retarded. The hardness and tensile strength of the cryorolled Al 6063 alloys have decreased upon subjecting it to annealing treatment (150–250 °C).
51 citations
TL;DR: In this article, a comparative study of aging and a combined treatment of short annealing and aging on mechanical properties and microstructure of cryorolled (CR) Al 6061 alloy is investigated by using tensile tests, hardness tests, electron backscattered diffraction and transmission electron microscope.
Abstract: A comparative study of aging and a combined treatment of short annealing and aging on mechanical properties and microstructure of cryorolled (CR) Al 6061 alloy is investigated in the present work by using tensile tests, hardness tests, electron backscattered diffraction and transmission electron microscope. The pre-CR solid solution treatment combined with post-CR short annealing (200°C, 5 min) followed by aging treatment (100°C, 57 h) of the Al 6061 alloy showed an improved ductility and well defined ultrafine grain structure as compared to the samples subjected to pre-CR solid solution treatment followed by post-CR aging treatment (100°C, 60 h).
27 citations