TY - JOUR

T1 - Mechanism of dynamic recrystallization and evolution of texture in the hot working domains of the processing map for Mg-4Al-2Ba-2Ca Alloy

AU - Suresh, Kalidass

AU - Rao, Kamineni Pitcheswara

AU - Prasad, Yellapregada Venkata Rama Krishna

AU - Wu, Chi Man Lawrence

AU - Hort, Norbert

AU - Dieringa, Hajo

N1 - Acknowledgments: The research work has been supported by a Strategic Research Grant (No. 7002744) from the City University of Hong Kong. The authors would like to thank to Chi Hung Yuen, Chalasani Dharmendra, and Ho Ying Ip for their help in compression tests, EBSD analysis, and microstructure work, respectively.

PY - 2017/12/2

Y1 - 2017/12/2

N2 - The occurrence of dynamic recrystallization (DRX) and its effect on the evolution of texture during uniaxial compression of a creep-resistant cast Mg-4Al-2Ba-2Ca alloy in the temperature range of 260-500 °C and strain rate range of 0.0003-10 s-1 has been studied using transmission electron microscopy and electron backscatter diffraction techniques with a view to understand its mechanism. For this purpose, a processing map has been developed for this alloy, which revealed two domains of DRX in the temperature and strain rate ranges of: (1) 300-390 °C/0.0003-0.001 s-1 and (2) 400-500 °C/0.0003-0.5 s-1. In Domain 1, DRX occurs by basal slip and recovery by dislocation climb, as indicated by the presence of planar slip bands and high dislocation density leading to tilt boundary formation and a low-intensity basal texture. On the other hand, DRX in Domain 2 occurs by second order pyramidal slip and recovery by cross-slip since the microstructure revealed tangled dislocation structure with twist boundaries and randomized texture. The high volume content of intermetallic phases Mg21Al3Ba2 and (Al,Mg)2Ca eutectic phase is considered to be responsible for the observed hot deformation behavior.

AB - The occurrence of dynamic recrystallization (DRX) and its effect on the evolution of texture during uniaxial compression of a creep-resistant cast Mg-4Al-2Ba-2Ca alloy in the temperature range of 260-500 °C and strain rate range of 0.0003-10 s-1 has been studied using transmission electron microscopy and electron backscatter diffraction techniques with a view to understand its mechanism. For this purpose, a processing map has been developed for this alloy, which revealed two domains of DRX in the temperature and strain rate ranges of: (1) 300-390 °C/0.0003-0.001 s-1 and (2) 400-500 °C/0.0003-0.5 s-1. In Domain 1, DRX occurs by basal slip and recovery by dislocation climb, as indicated by the presence of planar slip bands and high dislocation density leading to tilt boundary formation and a low-intensity basal texture. On the other hand, DRX in Domain 2 occurs by second order pyramidal slip and recovery by cross-slip since the microstructure revealed tangled dislocation structure with twist boundaries and randomized texture. The high volume content of intermetallic phases Mg21Al3Ba2 and (Al,Mg)2Ca eutectic phase is considered to be responsible for the observed hot deformation behavior.

KW - Hot deformation

KW - Magnesium alloy

KW - Microstructure

KW - Processing map

KW - Recrystallization

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=85037724139&partnerID=8YFLogxK

U2 - 10.3390/met7120539

DO - 10.3390/met7120539

M3 - Journal articles

AN - SCOPUS:85037724139

VL - 7

JO - Metals

JF - Metals

SN - 2075-4701

IS - 12

M1 - 539

ER -