Non-equilibrium intermixing and phase transformation in severely deformed Al/Ni multilayers

Abstract

Al/Ni multilayers have been prepared by repeated folding and cold rolling (F&R) of elemental foils. The thickness of Al and Ni foils is reduced down to less than 50 nm after fifty F&R cycles. Three-dimensional atom probe analyses clearly reveal the presence of supersaturated solid solutions and give the evidence of deformation-induced intermixing. The formation of the solid solutions and their transformation into the Al 3 Ni phase upon annealing is discussed.

The Effect of Strain on the Formation of an Intermetallic Layer in an Al-Ni Laminated Composite

“…It could not be asserted here whether or not any solid solution area of base metals has formed during CRB. However, it has been understood that intermixing of components is a necessary initial process before the occurrence of any phase formation [27].…”

“…It could not be asserted here whether or not any solid solution area of base metals has formed during CRB. However, it has been understood that intermixing of components is a necessary initial process before the occurrence of any phase formation [27]. Literature reports of the intermetallic formation mechanism in Al-Ni system emphasize on the composites, which were fabricated through ARB or F&R and subsequent annealing.…”

“…More rolling cycles gave rise to the development of a supersaturated solid solution [24]. Non-thermal diffusion, such as forced mixing or deformation-induced vacancies and dislocations, may promote intermixing of components at the nanoscale [27]. An intermetallic compound nucleates from this supersaturated solid solution after a short time of annealing at comparatively low temperature.…”

Grain boundaries in ultrafine grained materials processed by severe plastic deformation and related phenomena

“…An artificial way of preparing a multiphase nanostructured alloy can be derived from the ARB technique, using as starting material a sandwich structure made of different metals [87,88].…”

Modeling Enhanced Diffusion Mass Transfer in Metals during Mechanical Alloying

“…This phenomenon takes place during the synthesis of advanced powder materials by mechanical alloying (MA) in binary and multi-component systems, which is known as a versatile means for producing far-from equilibrium phases/structures possessing unique physical and chemical properties such as supersaturated solid solutions and amorphous phases (Benjamin, 1992;Koch, 1992;Koch, 1998;Ma & Atzmon, 1995;Bakker et al, 1995;El-Eskandarany, 2001;Suryanarayana, 2001;Suryanarayana, 2004;Zhang, 2004;Koch et al, 2010). Along with MA, this phenomenon is relevant to other modern processes used for producing bulk nanocrystalline materials by intensive plastic deformation (IPD) such as multi-pass equal-channel angular pressing/extrusion (ECAP/ECAE) (Segal et al, 2010;Fukuda et al, 2002), repetitive cold rolling (often termed as accumulative roll bonding-ARB, or folding and rolling-F&R) (Perepezko et al, 1998;Sauvage et al, 2007;Yang et al, 2009), twist extrusion (Beygelzimer et al, 2006) and high-pressure torsion (HPT) using the Bridgman anvils (X. . It is responsible for the formation of metastable phases such as solid solutions with extended solubility limits during IPD, demixing of initial solid solutions or those forming in the course of processing, and is considered as an important stage leading to solid-state amorphization in the course of MA.…”