Strong, stiff and tough diamond/metal laminate
Freestanding diamond foils are known to be exceptionally strong but brittle. The low fracture toughness is problematic for the applications, as catastrophic material failure cannot be tolerated in most cases. An approach to improve the fracture toughness is introducing weak interfaces into the material. Free-standing diamond foils were manufactured by means of chemical vapor deposition (CVD), stacked up with metal interlayers and bonded together. Three-point bending (3PB) tests were carried out on the laminated diamond. The diamond/metal laminate was strong and stiff and it was tougher than pure diamond foil. Theoretical analysis based on classical laminate theory (CLT) showed the same trend. Such multilayer coatings should be able to enhance the life of punch tools and injection moulding dies.