Which terms identify surface interaction processes such as adhesion, fusion, and peening?

• A. Adhesion, Fusion, Peening (Correct)
• B. Fusion, Welding, Soot
• C. Peening, Casting, Cracking
• D. Adhesion, Soot, Welding

Answer: (A)

Surface interaction processes describe how surfaces interact or are modified at the boundary between materials. Adhesion is the attraction and bonding that occurs between contacting surfaces, a fundamental surface-level interaction. Fusion refers to melting and bonding at the interface, creating a join across the surface. Peening is a mechanical surface treatment where impacts plastically deform the surface, altering its structure and inducing compressive stresses right at the surface. Together, these terms specifically describe how surfaces interact or are altered near the boundary, rather than broader manufacturing processes or byproducts.

The other options mix concepts that aren’t all surface-interaction terms: welding is a joining process that relies on fusion but is described as a broader process rather than a surface-interaction term; soot is a contaminant or byproduct; casting is a bulk forming process; cracking is a failure mechanism.