Novel deformation-induced polymorphic crystallization and softening of Al-based amorphous alloys. (1st April 2018)

• Record Type: Journal Article
• Authors: Bi, H.W.; Inoue, A.; Han, F.F.; Han, Y.; Kong, F.L.; Zhu, S.L.; Shalaan, E.; Al-Marzouki, F.; Greer, A.L.
• Is Part Of: Acta materialia. Volume 147(2018)
• Page Start: 90
• Page End: 99
• Publication Date: 2018-04-01
• Subjects: Amorphous alloy -- Crystallization -- Hardness -- AP-FIM -- HRTEM; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2018.01.016
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Melt-spun amorphous ribbons of Al90 Y10 (at.%) (90Al) and Al84 Y8.5 Ni4 Co2 Pd1 Fe0.5 (84Al) are cold-rolled at near to liquid-nitrogen temperature or at room temperature, inducing partial crystallization to nanoscale fcc-Al (α-Al). The crystallization is characterized and contrasted with the distinct sequences of reactions on annealing 90Al and 84Al amorphous alloys. Rolling-induced crystallization leads to softening, opposite to the effect of nanocrystallization induced by annealing. The origins of the hardness changes are analyzed. The rolling induces novel polymorphic crystallization to α-Al with extended solid solubility. This transformation, which occurs equally in 84Al and 90Al, despite the much greater thermal stability of the former, allows the ribbons to retain good bending ductility, and delays the onset of embrittlement on subsequent annealing. Partial crystallization induced by cold-rolling is useful in avoiding the formation of compound phases associated with brittleness, and is a promising process for high-solute Al-based amorphous alloys to be further developed as structural materials. Graphical abstract: Image 1