Atomistic investigation on adhesive strength of coupling agents to aluminum. (15th May 2023)

• Record Type: Journal Article
• Authors: Fukui, Naoki; Okunishi, Takaaki; Hara, Noyuki; Nakamura, Yoshinobu; Uetsuji, Yasutomo
• Is Part Of: International journal of mechanical sciences. Volume 246(2023)
• Publication Date: 2023-05-15
• Subjects: Multimaterials -- Necking -- Deformation mode -- Interatomic local strain -- Interfacial debonding -- Density functional theory; Mechanical engineering -- Periodicals; Génie mécanique -- Périodiques; Mechanical engineering; Maschinenbau; Mechanik; Zeitschrift; Periodicals; 621.05
• DOI: 10.1016/j.ijmecsci.2023.108150
• Languages: English
• ISSNs: 0020-7403

Abstract

Highlights: Atomistic adhesive strength is determined by the stiffness and occurrence of necking. Atomistic stiffness is dominated by proportion of bond angle change in overall deformation. The governing law of atomistic necking and breaking is established by interatomic local strain. Adhesive strength and failure mode were in agreement with DFT calculation and experiment. Atomistic adhesive strength could be verified in continuum mechanics by tensile tests and FEA. Abstract: For the adhesion of aluminum, which is of great importance in multimaterialisation, this paper focused on silane coupling agents as one of dominant factors. Amino, mercapto and EP silanes were employed as typical examples, then the atomistic adhesion mechanism was clarified through first-principles calculations and verified in continuum mechanics by tensile tests and finite element analysis. First-principles calculations revealed that the interfacial adhesive strength is governed by stiffness and occurrence of necking, even in atomistic stress-strain relationships. It was also found that stiffness correlates with the deformation mode of the molecular structure, and that necking occurs between the weakest bonds with small bond population and are determined by the interatomic local strain. Interfacial debonding occurred in both first-principles calculations and tensile tests, and the first-principles calculated values of interfacial adhesive strength were in qualitative agreement with the interfacial maximum stress values obtained by finite element analysis based on the breaking load during tensile tests of butt-bonded round bar specimens. Based on these results, this paper summarized effectiveness, applicable conditions and challenges of upscaling method from quantum mechanics to continuum mechanics. Graphical abstract: Image, graphical abstract