Analytical modeling and experimental investigation of laser induction hybrid rapid cladding for Ni-based WC composite coatings Shengfeng Zhou a,n , Xiaoqin Dai b , Haizhong Zheng a a School of Material Science and Engineering, Nanchang Hangkong University, Nanchang, Jiangxi 330063, PR China b School of Information Engineering, Nanchang Hangkong University, Nanchang, Jiangxi 330063, PR China article info Article history: Received 3 January 2010 Received in revised form 15 March 2010 Accepted 1 September 2010 Available online 29 September 2010 Keywords: Laser induction hybrid rapid cladding (LIHRC) Analytical modeling Ni-based WC abstract Laser induction hybrid rapid cladding (LIHRC) cannot only increase the cladding efficiency, but can also eliminate porosity and cracking of ceramic–metal composite coatings. In order to obtain a deep understanding of LIHRC with rapid cladding speed and high powder deposition rate, an analytical model of LIHRC for Ni-based WC composite coatings is proposed in the paper. The predictions of cladding height and powder efficiency obtained with this model are in good agreement with experimental results. Injection angles at which the attenuation rate of laser power is relatively low are identified and crack-free composite coatings with smooth surface, good profile and metallurgical bonding to substrate can be obtained. The calculated results for the temperature of the powder particles are compared to experimental data of the microhardness profiles and show a similar trend. & 2010 Elsevier Ltd. All rights reserved. 1. Introduction The laser cladding technique is an advanced process for producing metallurgically well-bonded coatings. Compared to conventional arc welding and thermal spraying, it can produce much better coatings, with minimum dilution, small heat- affected-zone (HAZ) and minimal distortion of the substrate. Thus laser cladding is now finding application in industry for the repair and rebuilding of components as well as laser engineered net shaping [1–3]. There are many processing parameters for laser cladding, such as laser mode, laser power, laser scanning speed, overlapping rate and powder deposition rate. Therefore, the established mathema- tical models of laser cladding are used to select reasonable parameters and to understand the mechanisms of laser cladding. Weerasinghe and Steen [4] developed a finite difference model to calculate the heat flux of laser cladding as early as 1983 and considered the effect of the powder particle cloud on the laser power. Huang et al. [5] also established an analytical model of laser cladding and theoretically investigated the interaction between the laser beam and the powder stream. Picasso et al. [6] proposed a simple and realistic model of laser cladding. The authors assumed that the cladding materials have been predeposited on the substrate to simplify the calculation. For a desired cladding height, given laser power, beam radius and geometry of the powder nozzle, the shape and temperature field of molten pool can be calculated by this model. Later, Kumar and Roy [7] established a 2-dimensional (2-D) finite volume model to calculate the equation of the heat conduction, and found that the preheated powder particles allowed a relatively higher laser cladding speed, resulting in thin cladding layer with low dilution. Summing up the published results, it is found that the above-mentioned models can help to understand the laser cladding process, but that most of them have assumed the shape of the molten pool as a priority or neglected the effect of the convection. As a result, those models have some differences in accuracy in the prediction of the effects of the processing parameters on the quality of the cladding layer. In recent years, 3-D transient finite element models were developed by Toyserkani et al. [8,9] for laser cladding with off- axial powder injection. They studied the effect of laser processing parameters such as laser power, scanning speed, pulse shape and powder feeding rat, on the geometry of cladding layer. After- wards, Fathi et al. [10] extended the above models and considered that the laser source was composed of infinite moving point heat source and used the superposition principle to solve the problem of the heat conduction. Cladding height, the depth of molten pool, dilution and temperature distribution of laser processing zone can be predicted by this model. Moreover, Wen et al. [11] proposed the modeling of coaxial powder flow for the laser direct deposition process. The model is capable of predicting the powder stream structure and multi-particle phase change process with liquid fraction evolution throughout the entire process while considering the particle morphology and size distribution in real powder samples. Partes [12] described an Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/optlastec Optics & Laser Technology 0030-3992/$ - see front matter & 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.optlastec.2010.09.001 n Corresponding author. Tel.: + 86 791 3863026. E-mail address: zhousf1228@163.com (S. Zhou). Optics & Laser Technology 43 (2011) 613–621