J Mater Sci Technol ›› 1999, Vol. 15 ›› Issue (06): 541-547.

• Research Articles • Previous Articles     Next Articles

Nonequilibrium Microstructures and Phase Evolutions of an Iron-based Laser Clad Coating

Xiaolei WU, Guangnan CHEN   

  1. Lab. for Nonlinear Mechanics of Continuous Media, Institute of Mechanics, The Chinese Academy of Sciences, Beijing 100080, China
  • Received:1998-10-04 Revised:1998-11-30 Online:1999-11-28 Published:2009-10-10
  • Contact: Xiaolei WU

Abstract: The microstructural and compositional features of the laser-solidified microstructures and phase evolutions occurring during high temperature tempering were investigated by using analytical electron microscopy with energy dispersive X-ray analysis. The cladded alloy, a powder mixture of Fe, Cr, W, Ni and C with a weight ratio of 10:5:1:1:1, was processed with a 3 kW continuous wave CO2 laser. The cladded coating possessed the hypoeutectic microstructure of the primary dendritic γ-austenite and interdendritic eutectic consisting of (γ+M7C3). Theγ-austenite is a nonequilibrium phase with extended solid solution of alloying elements. And, a great deal of fine structures, i.e., a high density of dislocations, twins, and stacking faults existed in austenite phase. During high temperature aging, the precipitation of M23C6, MC and M2C in austenite and in situ transformation of M7C3(+γ)→ M23C6 and M7C3+γ→M6C occurred. The laser clad coating revealed an evident secondary hardening and superior impact wear resistance.

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