Bulk nanostructured alloys prepared by flux melting and melt solidification

Abstract

We have prepared bulk nanostructured Ag60Cu40 alloys by a flux-melting and melt-solidification technique. The flux purifies the melts, leading to a large undercooling and nanometer-sized microstructure. The as-prepared alloys are composed of nanolayered Ag and Cu within micrometer-sized grains. The bulk nanostructured alloys have an ultimate tensile strength of approximately 560MPa, similar yield strength in tension and compression, elongation of 7% in tension, strain hardening exponent of 0.1, and relatively high mechanical and thermal stability up to 400°C.

Strength and plasticity of nanolaminated materials

“…Thus χ = 1. For example of Cu/Ni and Cu/Ag systems that hold the cubeon-cube orientation relation [17,18,30,39,51,[60][61][62], a small change in the magnitude of the slip vector at the interface poses a very minor resistance (or energy penalty) to slip, relative to the strength levels achievable in these materials. The strengthening effect in such kind of materials is thus ascribed to coherency stresses associated with the coherent interface as in Cu-Ni [29,50].…”

“…Nanolaminated materials can be processed in the form of thin films via bottom-up processes such as physical vapor deposition (PVD) [10,11] and electrodeposition [12], or in the form of bulk materials via top-down processes such as solid-state phase trans-CONTACT Jian Wang jianwang@unl.edu Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE68588, USA formation [13,14], accumulative roll bonding (ARB) [15,16], or solidification [13,17,18]. In epitaxial films, solid-state phase transformation, or eutectic solidification, energetically favorable crystallographic orientation relationships and interface habit planes develop naturally during synthesis [10,11,14,18].…”

Texture evolution via combined slip and deformation twinning in rolled silver–copper cast eutectic nanocomposite

“…Ag-Cu rods of eutectic composition (60-40 at% Ag-Cu) were cast into 0.95 cm bars of round cross section using a fluxmelting technique as described elsewhere (Shen et al, 2005(Shen et al, , 2007. After casting, rods were rolled longitudinally to 75%, 90%, and 95% nominal reductions in thickness from the starting diameter at either room temperature or at 200°C.…”

“…However, observations of similar narrow twin formations by the same authors in analogous filamentary Cu-Nb composites near the Nb filament-Cu matrix interface seem to suggest the former. Last, Ag-Cu composites have been subjected to large plastic deformation by rolling (Davy et al, 2008), wire drawing (Benghalem and Morris, 1997;Sakai and Schneider-Muntau, 1997;Hong and Hill, 1998;Ohsaki et al, 2003;Han et al, 2004), equal channel angular extrusion (Segal et al, 1997), and conventional mechanical testing (Shen et al, 2005(Shen et al, , 2007. In these the possibility of deformation twinning was not reported.…”

Microstructural Modulations Enhance the Mechanical Properties in Al–Cu–(Si, Ga) Ultrafine Composites

“…Recently, single step casting has been demonstrated to be a feasible method for the synthesis of bulk nano‐/ultrafine composites8–10 and using different approaches even a considerable plasticity could be introduced into high‐strength ultrafine eutectic alloys 11–16. For example, He et al .…”