Papers by Author: Zbigniew Świątek

Abstract: Microstructure and mechanical properties of NiAlV alloys of the composition belonging to the pseudo-binary Ni₃Al-Ni₃V cross-section were investigated. The samples were prepared by the cold crucible levitation melting (CCLM) and by re-melting and crystallizing in the small volume copper mould. The phase composition of the samples, with should result from the eutectoidal decomposition was not found. Instead the Ni₃(Al,V) and Ni(Al,V) solid solution or seldom disordered solid solution were retained due to the relatively high cooling rates. In the compression test the NiAlV alloys crystallized in the copper mould revealed high ductility and strength.

Abstract: At uniform excitation of semiconductors by laser radiation with pre-threshold power, locally melted regions are formed on irradiated surfaces. This is induced by thermo diffusive instability of a distribution of uniformly generated electron-hole plasma. The shapes of locally melted regions give rise to a great variety of interesting surface patterns. A mathematical model of the surface dynamics, when the instability of the melt front arises along a chosen wave vector, is proposed. The results of computer simulation of interface dynamics of solitary melted region are compared with experimental data.