TY - JOUR
T1 - Zn-22Al-2Cu alloy phase transformations at different homogenizing temperatures
AU - Dorantes-Rosales, Héctor Javier
AU - López-Hirata, Víctor Manuel
AU - Esquivel-González, Ramón
AU - González-Velazquez, Jorge Luis
AU - Moreno-Palmerin, Joel
AU - Torres-Castillo, Antonio
N1 - Funding Information:
The authors acknowledge the financial support from National Polytechnic Institute, SIP-IPN and National Council of Science, CONACYT.
PY - 2012/6
Y1 - 2012/6
N2 - The effect of the homogenizing temperature on phase transformations and hardening behavior was studied in a Zn-22Al-2Cu (wt%) alloy homogenized for 7 days at 315, 350, and 390 °C. The homogenized alloy was subsequently quenched and aged naturally at room temperature or artificially at 200 °C for different time periods. The β phase was unstable at room temperature and it decomposed through the β → α + η reaction during natural aging. An increase in the homogenizing temperature caused a decrease in the kinetics of the decomposition of the β phase in the alloy. Natural aging also caused an increase in the hardness due to the formation of nanometric grains with α and η phases and the presence of an intermetallic e phase. This result agrees with the time exponents (n) between 1.5 and 2.6, which were obtained using the Johnson-Mehl-Avrami-Kolmogorov equation for the decomposition of the β phase. The transformed fraction curves exhibited the fastest and slowest growth kinetics of the â phase decomposition at homogenizing temperatures of 350 and 390 °C, respectively. The artificial aging induced the formation of equilibrium phases and began a decrease in hardness due to the coarsening process of the equilibrium α, η, and τ' phases.
AB - The effect of the homogenizing temperature on phase transformations and hardening behavior was studied in a Zn-22Al-2Cu (wt%) alloy homogenized for 7 days at 315, 350, and 390 °C. The homogenized alloy was subsequently quenched and aged naturally at room temperature or artificially at 200 °C for different time periods. The β phase was unstable at room temperature and it decomposed through the β → α + η reaction during natural aging. An increase in the homogenizing temperature caused a decrease in the kinetics of the decomposition of the β phase in the alloy. Natural aging also caused an increase in the hardness due to the formation of nanometric grains with α and η phases and the presence of an intermetallic e phase. This result agrees with the time exponents (n) between 1.5 and 2.6, which were obtained using the Johnson-Mehl-Avrami-Kolmogorov equation for the decomposition of the β phase. The transformed fraction curves exhibited the fastest and slowest growth kinetics of the â phase decomposition at homogenizing temperatures of 350 and 390 °C, respectively. The artificial aging induced the formation of equilibrium phases and began a decrease in hardness due to the coarsening process of the equilibrium α, η, and τ' phases.
KW - Alloys
KW - Homogenization
KW - Phase transformation
KW - Scanning electron microscopy (SEM)
KW - X-ray diffraction
UR - http://www.scopus.com/inward/record.url?scp=84863833010&partnerID=8YFLogxK
U2 - 10.1007/s12540-012-3001-7
DO - 10.1007/s12540-012-3001-7
M3 - Artículo
SN - 1598-9623
VL - 18
SP - 385
EP - 390
JO - Metals and Materials International
JF - Metals and Materials International
IS - 3
ER -