Searching for evidence of strengthening from short-range order in the CrCoNi medium entropy alloy

TL;DR

This study investigates whether short-range order (SRO) enhances strength in the CrCoNi medium entropy alloy by analyzing a large dataset of mechanical measurements, finding no significant evidence of SRO-induced strengthening.

Contribution

The paper introduces a structurally agnostic analysis method to detect SRO effects in alloys, providing an upper bound estimate of SRO-induced strengthening.

Findings

No significant coupling of SRO to strengthening in CrCoNi.

Measurement scatter explains patterns suggesting SRO effects.

Provides an upper bound estimate of possible SRO-induced strengthening.

Abstract

The coupling of strength to short-range order (SRO) in the CrCoNi medium entropy alloy remains actively investigated, with conflicting reports supporting and opposing SRO-induced strengthening continuing to emerge. A direct observation of this effect is elusive, due to difficulties in the quantification of SRO. Here, we deliver a structurally agnostic analysis that instead searches for unusual patterns in crystal size effects as evidence of SRO-induced strengthening. For this purpose, we assemble a large dataset of strengthening measurements drawn from a range of thermomechanical processing conditions known to produce SRO. Based on a comparative analysis with pure metal benchmarks, we find no evidence for significant coupling of SRO to strengthening in CrCoNi, and that patterns suggesting a positive finding may be explained by cross-study measurement scatter. Nevertheless, we leverage our analysis to provide an upper bound estimate of SRO-induced strengthening in the unlikely scenario where other sources of scatter are negligible.