Deformation Mechanisms and Formability Window for As-Cast Mg-6Al-2Ca-1Sn-0.3Sr Alloy (MRI 230D)
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In: Journal of Materials Engineering and Performance, Vol. 27, No. 3, 01.03.2018, p. 1440-1449.
Research output: Journal contributions › Journal articles › Research › peer-review
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TY - JOUR
T1 - Deformation Mechanisms and Formability Window for As-Cast Mg-6Al-2Ca-1Sn-0.3Sr Alloy (MRI 230D)
AU - Suresh, Kalidass
AU - Pitcheswara Rao, Kamineni
AU - Chalasani, Dharmendra
AU - Yellapregada Venkata Rama Krishna, Prasad
AU - Hort, Norbert
AU - Dieringa, Hajo
PY - 2018/3/1
Y1 - 2018/3/1
N2 - The hot deformation characteristics of MRI 230D alloy have been evaluated in the temperature range 260-500 °C and strain rate range 0.0003-10 s−1, on the basis of processing map. The processing map exhibited two domains in the ranges: (1) 300-370 °C and 0.0003-0.001 s−1 and (2) 370-480 °C and 0.0003-0.1 s−1. Dynamic recrystallization occurs in the both domains with basal slip dominating in the first domain along with climb as recovery process and second-order pyramidal slip dominating in the second with the recovery by cross-slip. In Domains (1) and (2), the apparent activation energy values estimated using the kinetic rate equation are 143 and 206 kJ/mole, respectively, the first one being close to that for lattice self-diffusion confirming climb. It is recommended that the alloy is best processed at 450 °C and strain rates less than 0.1 s−1, where non-basal slip and cross-slip occur extensively to impart excellent workability. The alloy exhibits flow instability in the form of adiabatic shear band formation and flow localization at lower temperatures and higher strain rates. Forging of a cup-shaped component was performed under various conditions, and the results validated the predictions of the processing map on the workability domains as well as the instability regimes.
AB - The hot deformation characteristics of MRI 230D alloy have been evaluated in the temperature range 260-500 °C and strain rate range 0.0003-10 s−1, on the basis of processing map. The processing map exhibited two domains in the ranges: (1) 300-370 °C and 0.0003-0.001 s−1 and (2) 370-480 °C and 0.0003-0.1 s−1. Dynamic recrystallization occurs in the both domains with basal slip dominating in the first domain along with climb as recovery process and second-order pyramidal slip dominating in the second with the recovery by cross-slip. In Domains (1) and (2), the apparent activation energy values estimated using the kinetic rate equation are 143 and 206 kJ/mole, respectively, the first one being close to that for lattice self-diffusion confirming climb. It is recommended that the alloy is best processed at 450 °C and strain rates less than 0.1 s−1, where non-basal slip and cross-slip occur extensively to impart excellent workability. The alloy exhibits flow instability in the form of adiabatic shear band formation and flow localization at lower temperatures and higher strain rates. Forging of a cup-shaped component was performed under various conditions, and the results validated the predictions of the processing map on the workability domains as well as the instability regimes.
KW - hot forging
KW - hot workability
KW - kinetic analysis
KW - Mg-Al-Ca-Sn-Sr alloy
KW - microstructure
KW - processing map
KW - Engineering
UR - http://www.scopus.com/inward/record.url?scp=85042137411&partnerID=8YFLogxK
U2 - 10.1007/s11665-018-3219-8
DO - 10.1007/s11665-018-3219-8
M3 - Journal articles
AN - SCOPUS:85042137411
VL - 27
SP - 1440
EP - 1449
JO - Journal of Materials Engineering and Performance
JF - Journal of Materials Engineering and Performance
SN - 1059-9495
IS - 3
ER -