What are homogenous heterogenous and autogenous welding processe s?

A heterogeneous weld corresponds to a weld that is realized with a different filler alloy than the base metal. At the opposite, a homogeneous weld is realized with same filler alloy than the base metal. Finally, an autogenous weld is done without filler alloy. The joining is realized by melting only the base metal.

A.B.