Hot deformation behavior of Mg-2Sn-2Ca alloy in as-cast condition and after homogenization
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Hot deformation behavior of Mg-2Sn-2Ca alloy in as-cast condition and after homogenization. / Rao, K. P.; Prasad, Y. V.R.K.; Suresh, K. et al.
In: Materials Science and Engineering A, Vol. 552, 30.08.2012, p. 444-450.Research output: Journal contributions › Journal articles › Research › peer-review
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TY - JOUR
T1 - Hot deformation behavior of Mg-2Sn-2Ca alloy in as-cast condition and after homogenization
AU - Rao, K. P.
AU - Prasad, Y. V.R.K.
AU - Suresh, K.
AU - Hort, N.
AU - Kainer, K. U.
PY - 2012/8/30
Y1 - 2012/8/30
N2 - The hot deformation behavior of Mg-2Sn-2Ca (TX22) alloy has been characterized in the temperature range 300-500°C and strain rate range 0.0003-10s-1 using isothermal constant true strain rate tests. A processing map has been developed on the basis of flow stress data obtained as a function of temperature and strain rate, which revealed two windows or domains for hot working the alloy: (1) 300-370°C/0.0003-0.001s-1 and (2) 400-500°C/0.005-1s-1. Microstructural observations indicated that dynamic recrystallization occurs in both these windows with a finer resulting grain size in the first window. Apparent activation energy values of 183 and 178kJ/mole have been estimated in these windows, respectively and these are much higher than that for self-diffusion in Mg suggesting that considerable back stress is being generated due to the intermetallic particles (CaMgSn) present in the matrix. The mechanisms involving basal+prismatic slip and recovery by climb in the first domain and that of second order pyramidal slip and softening by cross-slip in the second domain are suggested to be occurring in these two domains. The processing map obtained on homogenized alloy is identical to that of the as-cast alloy suggesting that there is no benefit of homogenization treatment as regards hot workability and this is attributed to the thermal stability of the as-cast microstructure.
AB - The hot deformation behavior of Mg-2Sn-2Ca (TX22) alloy has been characterized in the temperature range 300-500°C and strain rate range 0.0003-10s-1 using isothermal constant true strain rate tests. A processing map has been developed on the basis of flow stress data obtained as a function of temperature and strain rate, which revealed two windows or domains for hot working the alloy: (1) 300-370°C/0.0003-0.001s-1 and (2) 400-500°C/0.005-1s-1. Microstructural observations indicated that dynamic recrystallization occurs in both these windows with a finer resulting grain size in the first window. Apparent activation energy values of 183 and 178kJ/mole have been estimated in these windows, respectively and these are much higher than that for self-diffusion in Mg suggesting that considerable back stress is being generated due to the intermetallic particles (CaMgSn) present in the matrix. The mechanisms involving basal+prismatic slip and recovery by climb in the first domain and that of second order pyramidal slip and softening by cross-slip in the second domain are suggested to be occurring in these two domains. The processing map obtained on homogenized alloy is identical to that of the as-cast alloy suggesting that there is no benefit of homogenization treatment as regards hot workability and this is attributed to the thermal stability of the as-cast microstructure.
KW - Dynamic recrystallization
KW - Hot deformation
KW - Magnesium alloy
KW - Plastic behavior
KW - Processing maps
KW - Engineering
UR - http://www.scopus.com/inward/record.url?scp=84862981402&partnerID=8YFLogxK
U2 - 10.1016/j.msea.2012.05.068
DO - 10.1016/j.msea.2012.05.068
M3 - Journal articles
AN - SCOPUS:84862981402
VL - 552
SP - 444
EP - 450
JO - Materials Science and Engineering A
JF - Materials Science and Engineering A
SN - 0921-5093
ER -