Influence of Alloying Elements on the Phase Structure, Stress–Strain Behavior, and Fracture Toughness of Ni3Sn: A First-Principles Study
Year: 2025
Type: article
Abstract: Transient liquid phase bonding (TLPB) encapsulation technology, as a valuable low-temperature bonding and high-temperature service joining technology, enables the preparation of encapsulated solder joints with the advantages of high-temperature resistance, good electromigration resistance, and low cost. However, the TLPB solder joints of the Ni-Sn system are prone to brittle fracture due to the formation of complex intermetallic compounds during reflow soldering, so it is of great engineering significance to improve the brittleness of intermetallic compounds of the Ni-Sn solder system. In this paper, the thermodynamic stability of the Ni3Sn phase after the addition of Co, Cu, and Pt alloying elements was firstanalyzed by phase structure formation energy and molecular dynamics calculations, the occupancy model of alloying elements in the crystal structure of Ni3Sn intermetallic compound phase was constructed, and the changes of lattice parameters, cell volume and densities of Ni6-xMxSn2 phase after the addition of alloying elements were simulated and calculated. The effects of alloying elements such as Co, Cu, and Pt on the stress-strain behavior and strength and toughness of Ni3Sn are evaluated using first-principles calculations, Pugh ratio (B/G ratio) and fracture toughness KIC calculations and stress-strain curve analyses of simulated tensile stretching, and a discussion on the applicability of toughness and brittleness discriminants, such as B/G, which are commonly used in computational materials science is made. Finally, the mechanism of the influence of alloying elements on the mechanical properties of Ni3Sn phases is illustrated from the electronic structure point of view by the density of states and Mulliken charge analysis.The results show that formation energy calculations show that the phase with Ni6-xMxSn2 structural model (M is the alloying element) is thermodynamically stable, and the additions of the alloying elements Co, Cu and Pt all reduce the theoretical molar volumetric shrinkage of the reaction process of Ni+Sn→Ni3Sn; the element Co increases the fracture toughness of Ni3Sn, whereas the elements Cu and Pt introduce Cu-Sn and Pt -Sn antibonds, reducing the bonding strength of the system and thus the toughness; the classical toughness-brittle criterion of B/G based on the energy theories of edge dislocations and solenoidal dislocations is not applicable in the Ni-M-Sn system due to the presence of metal, ionic and covalent bonds and the lack of slip systems in the hexagonal structure; Co elements reduce the anisotropy of the Ni3Sn phase, which in turn decreases the likelihood of microcracking in the welded joints in actual service; The formation of Ni6-xCoxSn2 can increase with the increase of Co element content, so the addition of low content of Co element can improve the toughness of Ni3Sn phase.
Source: Materials
DOI: 10.3390/ma18081792
Authors: Haotian Zhang, Jiaoyan Dai, Yinwen Cao, Yanjie Zhang, Mingdong Bao, Yanping Yin
Institutions: Ningbo University of Technology, Chang'an University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,137
OpenAlex ID: W4409462255