Precipitate stability in Cu–Ag–W system under high-temperature irradiation

Abstract

a b s t r a c tThe kinetics of precipitation was investigated in the ternary Cu alloy, Cu 83.5 Ag 15 W 1.5 during irradiation with MeV Kr ions at elevated temperatures. The alloy was prepared as a solid solution by physical vapor deposition and then irradiated at room temperature to create a high density of nano-sized W precipitates. These precipitates served as effective sinks for point defects during subsequent elevated-temperature irradiation, suppressing radiation-enhanced diffusion. As a consequence the size of the Ag precipitates formed during elevated-temperature irradiation was stabilized below 20 nm, up to temperatures in excess of 300°C, thus significantly extending the regime for ''compositional patterning'' above 175°C, found for Cu 85 Ag 15 . For higher temperature irradiations (above 400°C), the role of the W precipitates in stabilizing the size of the Ag precipitates switched from simply acting as point-defect sinks to serving as pinning sites for the Ag precipitates. At 500°C, the average Ag precipitate diameter is $30 nm compared to $300 nm in the Cu 85 Ag 15 binary alloy. Rate theory calculations and kinetic Monte Carlo simulations are employed to illustrate how this transition takes place.

Thermodynamics and kinetics of core-shell versus appendage co-precipitation morphologies: An example in the Fe-Cu-Mn-Ni-Si system

“…Very different precipitate morphologies have been observed in systems with two distinct precipitating phases [1]. These include core-shell structures [2,3], second-phase appendages (side-by-side coprecipitate) [4][5][6][7], or simply two spatially separate populations of precipitates [8][9][10]. These microstructures are determined by the coupling of many complex thermodynamic and kinetic factors.…”

Precipitate Stability in a Zr–2.5Nb–0.5Cu Alloy under Heavy Ion Irradiation

“…The main differences between type i and type iii structures are the amount of boundaries. Grain boundaries (GBs), or twin boundaries acting as net sinks for irradiation induced defects, have been observed in many metals such as Cu [35][36][37][38][39], Fe [40,41], Ni [42], and Zr [25,43], even though their sink strength is slightly different in the two cases. Singh et al [44], in a study on austenitic stainless steels, recognized that radiation-induced damage decreases with grain size because of defect trapping at GBs.…”

Mechanical behavior of nanocomposites

“…Thermal and irradiation stability, high-temperature strength 22,24,[28][29][30][31] Interfaces with location-dependent energies for interstitials Nanoscale confinement of helium precipitates at misfit dislocation intersections Helium management and outgassing in structural materials for nuclear energy 32,33 Ordered atomic-scale interfacial defect structure to influence deformation twin or glide dislocation nucleation barriers…”