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Effect of 0.4 wt% yttrium addition and heat treatment on the high-temperature compression behavior of cast AZ80

Author:
Ren, Lingbao, Zhou, Mingyang, Zhang, Yuwenxi, Boehlert, Carl J., Quan, Gaofeng
Source:
Journal of materials science 2019 v.54 no.7 pp. 5757-5772
ISSN:
0022-2461
Subject:
activation energy, alloys, annealing, deformation, heat treatment, temperature, yttrium
Abstract:
The effects of 0.4 wt% yttrium (Y) addition, annealing, and annealing + aging on the hot compression behavior of cast AZ80 were studied at strain rates between 10⁻⁴ and 10⁻² s⁻¹ and temperatures ranging between 573 and 673 K. The apparent activation energies of the as-cast AZ80 and AZ80 + 0.4Y were 122 and 182 kJ/mol, respectively. Shear bands formed in each alloys. Compared with the as-cast AZ80, more shear bands formed, and a larger volume of cracks initiated and propagated from the grain boundaries and shear bands in as-cast AZ80 + 0.4Y. In general, Y addition increased the peak stress at lower temperatures and higher strain rates. The annealed and annealed + aged alloys exhibited more shear bands and larger compressive peak stresses than their respective as-cast counterparts after compression at 573 K, 10⁻² s⁻¹. There were more shear bands in the annealed and annealed + aged AZ80 + 0.4Y compared with AZ80 after compression at 573 K, 10⁻² s⁻¹. Fine precipitates appeared in the shear bands of AZ80 + 0.4Y. The average width of the shear bands increased with increasing temperature and decreasing strain rate, and the angles of intersection between the different shear bands were approximately 90°.
Agid:
6274967