Element proportion effect on internal stress from interfaces and other microstructural components in Cu–Pb alloys

ABSTRACT

Polycrystalline materials like Cu–Pb alloy consist of four types of microstructural components, including grain cells, grain boundaries, triple junctions and vertex points, the mechanical properties of which governed by the atomic proportion of the alloy elements to a certain degree. The internal stresses from such microstructural components are quite different. Due to experimental limitations, the internal stresses from the alloy materials are difficult to measure directly, especially in the microstructural components. Here, we report a bottom-up approach using an atomistic calculation to obtain atomic properties in Cu-based alloy, as well as that in the microstructural components. The results reveal that a steep stress gradient exists at the interfaces of the alloy, which decreases significantly with the increase of the Pb. The defects evolution process in the alloy samples are investigated during tensile loading, revealing that the defect nucleation is delayed due to the decreasing von Mises stress gradient in the interfaces region as Pb increased. And the increased hydrostatic pressure in the interfaces regions, as a secondary factor can promote the defect nucleation. Among alloy samples with a grain size of 18.58 nm, that with 6.6 at.% Pb has minimal defects and the best mechanical properties.

KEYWORDS:

• Internal stress
• microstructural component
• alloy materials
• molecular dynamics

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Pengyue Zhao http://orcid.org/0000-0003-0977-6684

Additional information

Funding

The project is financially supported by the National Natural Science Foundation of China [grant number 51775146] and State Key Program of National Natural Science Foundation of China [grant number 51535003].