On the grain growth behavior of Ni-W alloys in the extremely fine-grained regime

TL;DR

This study investigates grain growth in nanocrystalline Ni-W alloys below 10 nm at 773K, revealing normal grain growth behavior characterized by parabolic kinetics and self-similar size distributions.

Contribution

It provides new insights into grain growth mechanisms in ultra-fine Ni-W alloys, focusing on sizes below 10 nm, which were less explored in prior research.

Findings

Normal grain growth observed below 10 nm

Parabolic kinetics confirmed grain growth behavior

Self-similar size distribution in log-normal plot

Abstract

Nanocrystalline pure FCC metals and some alloys are known to exhibit abnormal grain growth. Addition of solutes, such as W, has led to improved grain size stability in nanocrystalline Ni. While several groups have investigated grain growth behavior in Ni-based binary alloys, grain sizes greater than 15 nm were primarily investigated. In the present study, grain growth behavior is examined in grain size regime below 10 nm in nanocrystalline Ni-W alloys with 8 to 15 at% W at 773K. In this size regime, normal grain growth behavior was observed in these alloys, evidenced from (a) parabolic kinetics in plots of square of average grain size against annealing time, and (b) statistical self-similarity on the scaled size distribution in a log-normal plot.