Preparation And Performance Of Zr-Cu-Ni-Al-Y Metallic Glass Matrix Composite Coatings Prepared By Laser Cladding

Corrosion is one of the most common failure modes of metallic materials,and corrosive environments are usually accompanied by erosion and other wear.Therefore,improving the corrosion resistance of metal materials is of great importance.Metallic glasses(MGs)have unique structure with short-range order and long-range disorder,which avoids the defects such as vacancies,dislocations and grain boundaries in common crystal materials and endow the MGs with high hardness and excellent corrosion resistance.Metallic glass matrix composite coatings(MGMCCs)prepared by laser cladding can effectively improve the hardness and corrosion resistance of the metal substrate,but the microstructure evolution and performance of the coatings in the process still needs intensive study to obtain MGMCCs with high-performance.Zr-Cu-Ni-Al MG alloy system has strong glass forming ability and relatively excellent corrosion resistance,without containing noble metals or highly toxic elements such as Be.These make the Zr-Cu-Ni-Al MGs very suitable for application as corrosion-resistant coatings.However,the Zr-Cu-Ni-Al MG system is very sensitive to oxygen,and it is quite easy to be oxidized,which will causes the crystallization performance degradation.By adding Y element into the alloy,stable Y₂O₃ can be formed to reduce the oxygen content in the MG matrix.Therefore,(Zr₅₅Cu₃₀Ni₅Al₁₀)₉₉Y₁ alloy was selected in this paper as the research material,and Zr-Cu-Ni-Al-Y MGMCCs were prepared by laser cladding on 45steel substrates.This paper systematically studied the influence of laser power on the microstructure of Zr-Cu-Ni-Al-Y MGMCCs.The hardness distribution as well as the corrosion resistance in1 mol/L H₂SO₄ of the coatings were investigated.It was found that the coating is relatively dense and exhibits a good metallurgical bonding with the substrate.Crack-free coatings can be obtained under high MG content.The coating is mainly composed of MG and intermetallic compounds such as Cu Zr₂,Ni Zr₂ and Cu Zr.Y₂O₃ is the heterogeneous nucleation core of the intermetallic compound.The MG content shows a downward trend with increasing laser power.The hardness of the prepared coating is up to 571.3 Hv,which is about 2.5 times higher than that of the 45 steel substrate.Corrosion mainly occurs at the interface between the MG matrix and the intermetallic compound in the overlap zone.When the scanning rate is 1 m/min and the laser power is 900 W,the coating exhibit the best corrosion resistance.The corrosion potential is-0.55 V and the corrosion current density is3.38×10^-8 A/cm².The corrosion resistance of the coatings is significantly better than that of the 45 steel substrate and the commonly used 316L stainless steel.The MGMCCs were further treated by laser remelting,and the influence of laser remelting on the microstructure,hardness and corrosion resistance of the coatings were studied.It was found that the content of MG in the coating significantly increased after remelting.Coatings with high MG content could be obtained by laser remelting treating.The pores in the remelted area were significantly reduced.The hardness of the remelted coating is slightly lower than that without remelting,and the hardness distribution in the remelted coating is more uniform.The corrosion of the remelted coating mainly occurs at the interface between the small amount of crystalline phase and the MG substrate in the overlap area.Although the corrosion current density of the remelted coating is close to that without remelting,the corrosion potential is significantly increased,indicating a relatively excellent corrosion resistance performance of the remelted coatings.In this paper,crack-free Zr-Cu-Ni-Al-Y MGMCCs were prepared by laser cladding.The microstructure evolution,microhardness and corrosion behavior of the coating were systematically studied,and laser remelting was used to obtain coatings with high MG content,which can further improve the corrosion resistance of the coatings.Related research provides effective theoretical and technical supports for the preparation and optimization of MG based corrosion-resistance coatings.