Crack initiation of printed lines predicted with digital image correlation

TL;DR

This paper investigates crack initiation in printed metallic films using digital image correlation and confocal microscopy, revealing that cracks start earlier in thicker, defect-rich regions during tensile testing.

Contribution

It introduces the application of digital image correlation with confocal microscopy to visualize crack initiation in printed metallic films.

Findings

Cracks initiate earlier in thicker, defect-prone regions.

Digital image correlation effectively visualizes crack initiation.

Thicker areas show higher defect density and earlier cracking.

Abstract

Printing of metallic films has been preferred for roll-to-roll processes over vacuum technologies due to faster processing times and lower processing costs. Films can be produced by depositing inks containing suspended metallic particles within a solvent and then heating the films to both remove the solvent and sinter the particles. The resulting printed structure, electrical and mechanical behavior of the printed films has been studied to better understand their electro-mechanical response to loading and eventual brittle fracture. This study evaluated the electro-mechanical behavior of 1.25 {\mu}m printed Ag films using in-situ resistance and in-situ imaging methods. Digital image correlation was utilized with confocal laser scanning microscope images to better visualize crack initiation during tensile straining. This technique showed that cracks initiated earlier in the thicker areas of the film (crests) than in lower areas (troughs) because of a higher density of printing defects and the increased thickness.