| SUN Qi,LI Zhi-yong,ZHANG Ying-qiao,YANG Liu-qing,LIU Che-kai,CHENG Kai-qi.Microstructure and Properties of Laser Cladding Al-TiC Coating on AZ91D Magnesium Alloy[J],46(1):40-44 |
| Microstructure and Properties of Laser Cladding Al-TiC Coating on AZ91D Magnesium Alloy |
| Received:September 06, 2016 Revised:January 20, 2017 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2017.01.007 |
| KeyWord:laser cladding magnesium alloy Al-TiC coating cermet micro-hardness corrosion resistance |
| Author | Institution |
| SUN Qi |
Welding Research Center, North University of China, Taiyuan , China |
| LI Zhi-yong |
Welding Research Center, North University of China, Taiyuan , China |
| ZHANG Ying-qiao |
Welding Research Center, North University of China, Taiyuan , China |
| YANG Liu-qing |
Welding Research Center, North University of China, Taiyuan , China |
| LIU Che-kai |
Welding Research Center, North University of China, Taiyuan , China |
| CHENG Kai-qi |
Welding Research Center, North University of China, Taiyuan , China |
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| Abstract: |
| In order to improve micro-hardness and corrosion resistance of magnesium alloy coating by studying the characteristics of microstructure and properties of Al-TiC coating. Al-TiC laser cladding layer on AZ91D magnesium alloy was prepared by using Nd: YAG solid laser. Microstructure morphology, phase structure, micro-hardness and corrosion resistance of the cladding layer were investigated with the aid of optical microscope (OM), X-ray diffraction (XRD) measurement, micro-hardness tester and electrochemical workstation. It can be seen that the Al-TiC coating were mainly composed of AlTi3(C,N)0.6, Al3Mg2, Mg2Al3, Al, TiC, etc. The thickness of the laser cladding layer was about 0.35 mm. The surface of laser cladding was well formed, and the grain size of the interface layer was refined. There was a good bond between the Al-TiC coating and the substrate, and it presented the shape of a big wave. The average micro-hardness of cladding layer sample was 224 HV, which was about four times of the matrix micro-hardness (62 HV), thus indicating that Al-TiC coating had significant potentiation to AZ91D magnesium alloy. The self-corrosion potential of magnesium alloy substrate was -1.475 V. Its current density of self-corrosion was 7.556×10–5 A/cm2. The self-corrosion potential of the cladding layer sample was -1.138 V. And the current density of self-corrosion was 4.828×10–5 A/cm2. Compared with the magnesium alloy substrate, corrosion potential value of the cladding layer increased, the corrosion current density value decreased and the corrosion resistance of cladding layer could be improved. Using laser cladding technology can prepare Al-TiC coating on AZ91D magnesium alloy. Since the existence of hard phase AlTi3(C,N)0.6, Al3Mg2, Mg2Al3, TiC, etc., micro-hardness and corrosion resistance of cladding layer can be increased dramatically. |
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