A Co - Cr -Mo laser cladding applied on railway wheels is characterised by a combination of EBSD and EDX. A complete pass of the cladding is investigated to achieve a better understanding of the microstructure evolution during laser cladding. A microstructure with columnar grains extending over the whole thickness of the cladding is observed. During laser cladding, a pronounced columnar grain structure is formed in the coating. Each columnar grain consists of sheaves of fine cells and/or dendrites. Two different precipitates, a carbide and a non-equilibrium phase, form in the cell walls of the columnar grains during solidification. Adjacent cells or dendrites are separated by low-angle grain boundaries having a misorientation of about 2 degree. The grain boundary misorientation-angle distribution of the grains is random. In the case of multiple cladding, the grains in the first layer serve as seeds for grains in subsequent layers. Therefore, some of the grains can grow from the substrate over the whole thickness of the coating. Cladding produced from an alloy having low stacking-fault energy may contain stacking faults caused by thermal strains and residual stresses. EBSD analysis is well suited for microstructural analysis of such materials. Phase analyses are best performed by combining EBSD and EDX analysis.
Microstructural characterisation of a Co-Cr-Mo laser clad applied on railway wheels
International Journal of Materials Research - Zeitschrift für Metallkunde ; 97 , 6 ; 838-844
2006
7 Seiten, 12 Bilder, 8 Tabellen, 26 Quellen
Aufsatz (Zeitschrift)
Englisch
Engineering Index Backfile | 1940
Engineering Index Backfile | 1942
Engineering Index Backfile | 1920
|Pulse excitation of railway wheels
TIBKAT | 1969
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