Investigation of ideal shear strength of dilute binary and ternary Ni-based alloys using first-principles calculations, CALPHAD modeling and correlation analysis

TL;DR

This study predicts the ideal shear strength of dilute Ni-based alloys using first-principles calculations and CALPHAD modeling, revealing how alloying elements influence shear strength and the key atomic features affecting it.

Contribution

It combines DFT and CALPHAD approaches to model and analyze the composition dependence of shear strength in Ni alloys, providing new insights into atomic bonding effects.

Findings

Shear strength increases with Mn, Fe, Co up to 8.3% alloying.

Shear strength decreases with Nb, Si, Mo, Ti, Al, Cr.

Lattice constant and elastic constant C11 are key factors affecting shear strength.

Abstract

In the present work, the ideal shear strength ({\tau}_is) of dilute Ni34XZ ternary alloys (X or Z = Al, Co, Cr, Fe, Mn, Mo, Nb, Si, Ti) are predicted by first-principles calculations based on density functional theory (DFT) in terms of pure alias shear deformations. The {\tau}_is results show that within the concentration up to 8.3% of alloying elements, {\tau}_is increases with composition in binary systems with Mn, Fe, and Co in ascending order, and decreases with composition with Nb, Si, Mo, Ti, Al, and Cr in descending order. The composition dependence of {\tau}_is in binary and ternary systems is modeled using the CALculation of PHAse Diagrams (CALPHAD) approach considering lattice instability, indicating that atomic bonding strength significantly influences {\tau}_is. Correlational analyses further show that lattice constant and elastic constant C11 affect {\tau}_is, the most out of the elemental features.