Research On Process Experiment Of Laser Cladding Repairing With FGH95 Nicked-based Alloy Powder

Laser Cladding Repairing(LCR) is an advanced laser repairing technology that has been developed based on Laser Rapid Prototyping(LRP). LCR introduces the principle of LRP into the repairing processing of components, that the impairment can be repaired through cladding the same powder materials to the damaged surface according to the outline of damaged components, and the original outline dimension and properties can be reproduced. FGH95,which is one of Nicked-based alloy powder materials, has become the best material of aero-engine turbine disc due to its good performance, such as fine grain size, homogeneous microstructure ,non-macrosegregation, high yield strength and good fatigue property.In this paper, the LCR experiment with FGH95 powder was performed. The fusion mechanism of interface between the repairing part and the substrate was studied. The effect of processing parameters on the micro-hardness of samples and the cause and prevention measures of the ill bonding in the repairing processing were analyzed. The main works were as following:(1) The mechanism of LCR was intensive studied. Heat conduction, convection and mass transfer in the melting processing of LCR were analyzed respectively.(2) A series of based experiments of LCR with FGH95 were performed. And the effect of processing parameters on surface morphology of repairing components was analyzed. The results indicated that good surface morphology of repairing part could be achieved on the laser cladding condition which were laser current I=300A, defocus distance f=+8mm, scan rate v=180mm/min and scan line spacing h=1.0mm.(3) The micro-structure of the fusion zone of the repairing specimen was studied. And the fusion mechanism of interface of the fusion zone was analyzed. It was found that compact micro-structure was made up of tiny cell-like crystal, coarse dendrite, small dendrite and cell-like crystal from bottom to top.(4) The distribution of micro-hardness and the effect of processing parameters on the micro- hardness of the samples were studied. With increasing the distance away from the surface, the value of micro-hardness decreased gradually.(5) The cause and prevention of the ill bonding in the repairing processing were analyzed.