Question

why is solid - state welding useful for joining dissimilar metals?
a it joins metals without melting, avoiding defects from different melting points.
b it works best only on aluminum and copper.
c it uses low - cost filler rods to fuse materials.
d it melts both materials at very high temperatures.

Explanation:

To determine the correct answer, we analyze each option:

• Option A: Solid - state welding joins metals without melting them. When joining dissimilar metals, different melting points can cause defects in fusion - based welding (like melting one metal but over - melting or under - melting the other). So avoiding melting helps in preventing such defects, which makes this option correct.
• Option B: Solid - state welding is not limited to just aluminum and copper. It can be used for a wide range of dissimilar metals, so this option is incorrect.
• Option C: Solid - state welding does not typically use filler rods to fuse materials. Filler rods are more associated with fusion - based welding processes, so this option is incorrect.
• Option D: Solid - state welding does not melt the materials. The name "solid - state" implies that the materials remain in the solid state during the welding process, so this option is incorrect.

Answer:

A. It joins metals without melting, avoiding defects from different melting points.