Microstructure Characterization Of Laser Cladding H13-TiC Composite Material

Laser cladding have been widely used to modifying surfaceperformances，such as corrosion resistance，wear resistance，anti-oxidantlayer，high hardness and so on. Moreover，it can be used to repaire partialfailure surfaces. Under the harsh working conditions，dies steel are failedeasily，which always lead to huge economic losses. In this paper，H13-TiCcomposite coatings with different contents of TiC were achieved by lasercladding on the H13die steel substrates. The crystalline phase morphology，microstructure，composition and micro-distribution of the external andinternal laser cladding layer were characterized by X-ray diffraction（XRD），scanning electron microscopy（SEM），transmission electronmicroscopy（TEM），scanning transmission electron microscopy（STEM）and X-ray energy dispersion spectrum（EDS）. The corrosion resistance of the laser cladding layer were tested by anodic polarization curve，and theresults were associated with the content and microstructure of TiC in thelaser cladding layer. Based on the above research，following conclusionscan be drawn：（1）After laser cladding the H13-TiC powder，the surface ofcladding layer are composed of the phase of substrate，reinforcing phaseTiC and the oxides of Ti. In the interior of cladding layer，the new phaseare not found，which meant TiC is not react with the element of H13diesteel.（2）With the increase of TiC content，the shape of TiC in the lasercladding layer is changing from round，quadrilateral and irregular at thelow content of TiC to radial-flower and cluster-flower at the high contentof TiC. The different morphology of TiC crystal particle grow to generatethe most stable form in accordance with the laws of crystal growthkinetics.（3）The anodic polarization curve of the laser cladding layer withdifferent content of TiC shows that：compared with the H13die steel，corrosion potential of the laser cladding layer is markedly increased，andthe corrosion current is markedly reduced，which indicate that lasercladding layer caused a pronounced improvement in corrosion resistance.But with the increase of TiC content，the corrosion resistance is notincreasing linearly. When the content of TiC is15wt.%，the corrosionresistance achieve optimal.