Analysis of microcracks at the edges of micro tapered holes machined by in-situ laser-assisted imprinting and its inhibition methods

• Published in: Materials & design Vol. 256; p. 114336
• Main Authors: Meng, Siwei, Shi, Guangfeng, Zhang, Jifeng, Yao, Dong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2025; Elsevier
• Subjects: In-situ laser-assisted imprinting; Micro tapered holes; Microcracks; Molecular dynamics; Microcracks; In-situ laser-assisted imprinting; Molecular dynamics; Micro tapered holes
• ISSN: 0264-1275
• DOI: 10.1016/j.matdes.2025.114336

[Display omitted] •Simulating the micro tapered holes forming by MD.•Establishing a mechanical model with R2 = 0.92906.•Proposing the critical parameters of In-LAI to suppress micro-cracks. Micro tapered holes find extensive use in various domains including detection, infusion, lighting, etc. In-situ Laser-assisted micro-imprinting (In-LAI) technology is an effective method for machining micro tapered holes. However, the problem of microcracks at the edge of the outlet of the micro tapered holes are difficult to control, which affects the service life and the use of the effect of the parts. In this study, by MD simulation, the accumulated high potential energy defects during the micro tapered holes forming process have been shown to be the main factor for micro-cracks germination; A mechanical model of T2 copper material fracture toughness with size effect and temperature dependence of R2 = 0.92906 has been established, which is in accordance with the Hall-Petch relation and is used to guide the selection of process parameters thresholds for suppressing micro-cracks germination. The results have shown that workpiece temperature is >600 K, indenter taper angle is less than 90°, and the grain size of the material is <4 μm. This study systematically realizes the machining of the high-quality micro tapered holes and contributes to the field of micro-forming, and laser assisted machining.