Journal of Inorganic Materials ›› 2013, Vol. 28 ›› Issue (9): 1033-1039.doi: 10.3724/SP.J.1077.2013.12730

• Research Paper • Previous Articles     Next Articles

Microstructure of Al2O3/Ti-Al Composite Coatings Prepared by Laser Aluminum Thermal Reduction Processing

ZHANG Xiao-Wei, LIU Hong-Xi, JIANG Ye-Hua, PHAM THI Hong-Nga   

  1. (Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China)
  • Received:2012-12-03 Revised:2013-01-08 Online:2013-09-20 Published:2013-08-14
  • Contact: JIANG Ye-Hua. E-mail:jiangyehua@kmust.edu.cn
  • About author:ZHANG Xiao-Wei. E-mail: zhxw72@163.com
  • Supported by:

    National Natural Science Foundation of China(51261013); Analysis and Testing Foundation of KMUST(2010025, 2011008)

Abstract: With composite powders of Al and TiO2 systems as reactants, Al2O3 reinforced Ti-Al matrix intermetallic composite coatings were prepared on the TC4 alloy substrate by laser in-situ synthesis processing. The effects of laser power, laser scanning speed and laser spot size on laser energy density were analyzed, respectively. The macroscopic morphology, cross-section microstructure, and micro-hardness of Al2O3/Ti-Al composite coatings were characterized by optical microscope (OM), X-ray diffraction (XRD), energy dispersive spectroscope (EDS) and micro-hardness tester. The results show that scanning speed has the greatest impact on laser energy density firstly, then the laser spot size, and then the weakest is laser power. With the scanning speed increases, Al2O3/Ti-Al composite coatings surface become rougher, “fish-scale shape” morphology are more obvious, and the thickness of bonding-zone decreases. The reinforced phase of composite coating is composed of k-Al2O3 and α-Al2O3, while the matrix phase is composed of α-Ti and α2-Ti3Al. And with the increase of laser scanning speed, k-Al2O3 changes into α-Al2O3 partially. The morphology of Al2O3 reinforcement tends to change from dendrite shape to fiber. The micro-hardness of samples has a smooth transition tendency from the substrate to the coating surface. The micro-hardness distribution of coating cross section is uniform, and the average micro-hardness is significantly higher than that of the substrate.

Key words: laser cladding, in-situ synthesis, aluminothermic reduction, Al2O3/Ti-Al composite coating, TC4 alloy

CLC Number: 

  • TB333