Constrained groove pressing and subsequent annealing of Al-Mn-Si alloy: Microstructure evolutions, crystallographic transformations, mechanical properties, electrical conductivity and corrosion resistance

Publication date: 15 June 2017
Source:Materials & Design, Volume 124
Author(s): Hesam Pouraliakbar, Mohammad Reza Jandaghi, Gholamreza Khalaj
Al-Mn-Si specimens were severe plastic deformed (SPDed) through constrained groove pressing (CGP) by εeff=1.16, 232, and 3.48. CGPed sheets were subsequently annealed at 150, 250 and 350°C to investigate complementary treatment route on macro- and microscale properties of heavily strained alloy. Microstructure evolutions in deformed and post-annealed states along with their associated mechanisms such as recovery, recrystallization and strain induced grain boundary migration (SIGBM) were studied and analyzed. SIGBM as an indication for inhomogeneous grain growth was traced by transformations in grains' aspect ratio. Microanalysis of crystallographic characteristics by means of X-ray diffraction (XRD) patterns revealed that (111) planes were the main crystallographic index in CGPed and annealed alloys since preservation up to 350°C had amplified the (200) and deteriorated the intensity of (311) planes. Dislocation density measurements implied the dynamic recovery occurrence in CGP (εeff=2.32) which had affected mechanical characteristics, electrical conductivity and corrosion resistance of the utilized alloy. Mechanical properties through tension and hardness tests had been examined since the maximum YS, UTS, and hardness of 118MPa and 141MPa, 52Hv obtained for CGPed specimen (εeff=3.48) compared with annealed alloy with the values of 85MPa and 112MPa, and 29Hv, respectively.

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