The Study Of Alloy Coatings By Laser Cladding Fe-base And Ni-base On Aluminum Alloy

Aluminum alloy are widely used today for some fields in aircraft、automobile,etc.,because of their excellent properties，such as low density, high specificstrength and good formability. However, there are a series of problems, such as lowhardness, big friction coefficient, poor wear resitance, etc., this greatly limits theapplication of aluminum alloy. In order to improve the wear resitance of aluminum alloy,this paper adopt the technology of laser cladding to produce the Ni-based and Fe-basedcoatings on the surface of aluminum alloy, and research technological parameter of laser、maro morphology of cladding layers、microhardness、XRD、microstructureand wearresistance; and investigate influence of the activator to cladding size.Ni60alloy powder was cladded by YAG laser on the surface of ZL114A aluminumalloy. The research shows the Ni-based coating with good macro quality and metallurgicalboading to the substrate can be obtained under optimization of processing parameters, theaverage thickness of coating is about0.4mm; the average thickness of coating is518HV,the hardness of coating increases2³times in comparison to the substrate; the claddinglayer is consisted of Ni₄Al₃、Ni₂Al₃、AlNi、Fe₃Si、Ni₃Al phases; the wear volume ofZL114A substrate is1.8132mm³, the wear volume of Ni-based coating is0.3333mm³,thewear resistance of coating increases5.44times in comparison to the substrate; Besides, theaddition of SiO₂activator contributes to increase the fusion depth and the fusion width.Thewear mechanism of ZL114A follow serious adhesive wear and plough trenches way causedby plastic deformation, the wear mechanism of Ni-based follows abrasive wear andadhesive wear.The mixed powder of pure Fe powder and Al powder in four different proportionwere cladded by CO₂laser on the surface of ZL114A aluminum alloy, they are pespectively60Fe-40Al（wt.%）、70Fe-30Al（wt.%）、80Fe-20Al（wt.%）、90Fe-10Al（wt.%）. The researchshows the Fe-Al coating with good macro quality and metallurgical boading to thesubstrate can be obtained under optimization of processing parameters. The thickness ofcoatings reached0.9¹.2mm;the average thickness of four coatings are respectively311HV、363HV、537HV、569HV, the hardness increases5⁶times in comparison to thesubstrate; the wear volume of four coatings are respectively0.4607mm³、0.3648mm³、0.3073mm³、0.3043mm³,the wear volume of ZL114A substrate is1.8132mm³.The wearresistance of coatings in different proportions were improved to different degrees incomparison to substrate.The wear mechanism of60Fe-40Al、70Fe-30Al follow mainly the spalling wear, the wear mechanism of80Fe-20Al、90Fe-10Al follow mainly the abrasivewear.In a word, the generation of Ni-based and Fe-Al coatings on the surface of aluminumalloy by laser cladding will greatly improve the surface hardness and wear resistancebecause of a series of Ni/Al and Fe/Al compound.