In situ laser irradiation of WC-Co hard metals inside an SEM. Part 2. Behaviour of the cobalt binder.

Cemented carbides with higher binder contents were irradiated with a CO2-pulse laser within a SEM to investigate the structural development in more detail. The decisive medium is the melting binder which dissolves the refractory carbide phase. In this way a superficial layer of an oversaturated solid solution with highly dispersed secondary carbides is produced. At higher pulse numbers a periodic structure is engraved in the surface by local evaporation as result of a self-amplifying resonance phenomenon.