Laser Cladding On The Surface Of Aluminum Alloy

Aluminium alloy is a kind of clored metal which has the largest used quantity. It's mostly used in the field of spaceflight and power machine. But because its low rigidity which limits its more application. Laser cladding can improve the rigidity of aluminium alloy availably. Laser cladding is a kind of case strengthening technique have been developed for some twenty years, which has some unique advantages compared with the common cladding processes.By means of CO₂ laser, wear resistance coatings have been obtained by laser cladding Al-Si, Al-Si+SiC, Al-Si+Al₂O₃, Cu-Al on aluminium alloy in the study of this paper. There is few research about these cladding materials at home, so this article mostly discusses whether these cladding material can be cladded on the surface of aluminium alloy and what about the capability after cladding. The microstructure and properties of the cladding coatings have been analyzed and tested by use of a series of modern physical test means.Al-Si composite coatings have been successfully fabricated on the aluminium alloy via the preset-powder cladding process. And the laser cladding processing has been studied. Argon used as shielding gas, sound coatings can be fabricated with the optimum processing parameters. The coatings have smooth and continuous surface, and metallurgically bond to the substrate. In the bottom and low-mid zones of the clad, the matrix grains are finely cellular or cell-dendrite. In up-mid and top are fine dendritic and equiaxial grains. The results show that rigidity property of the coatings are 1 times of respective substrates. For SiC cladding layer, the results show that rigidity and resistance property of the coatings are 3 times of those of respective substrates due to dispersal strengthening of both SiC and other separated-out dispersal phase, solid dissolving strengthening and finer crystal particle which results from the rapid heating and cooling of laser cladding. For Al₂O₃ cladding layer, the cladding coatings with optimum processing parameters have little dilution by the substrate and good bonding to the substrate. The results show that rigidity property of the coatings are 2 times of respective substrates. In experiment the phenomenon that cracks rise up in the clad and has been explained. The solutions for settling the phenomenon were putted forward.The results show that these new cladding materials were well bonded with aluminium alloy by laser cladding and the rigidity property of aluminium alloy wasgreatly improved.