Substrate failure
The substrate failure is a fracture within the bonded parts. The adhesive joint itself remains intact. The performance of the adhesive itself is higher than the performance of the substrates.
Adhesive (adhesion + cohesion) > cohesion of the bonded substrates
In the fracture mechanics test, the substrate fracture is usually considered positive evidence of a successful bond.
In the case of mixed fracture, the destruction occurs in the immediate vicinity of the solidified adhesive layer.
Substrate failures can be influenced by several factors:
To evaluate and prevent substrate failures, it is important to consider both the mechanical properties of the adhesive and the adherend material. Careful material selection and process control are critical to ensure that the bond meets the requirements and that no unwanted substrate failures occur.