Study On?Cu,Ni?-La₂O₃/Gd₂O₃ Gradient Functional Composites

The?Cu,Ni?-La₂O₃/Gd₂O₃ gradient functional composites were prepared on pure Cu matrix by laser additive manufacturing technology The microstructure of the powder raw material was distributed,and the influence of laser power on the deformation amount was studied.The tribology and electrical ablation properties of the gradient material with reasonable deformation were tested.The microstructure analysis showed that the elemental distribution of the?Cu,Ni?-La₂O₃/Gd₂O₃ gradient materials prepared by these two ratios showed a gradient change,and the mechanical properties showed a gradient change.The microstructure of the?Cu,Ni?-La₂O₃ gradient functional composite:the bottom structure is a long-shaped dendritic structure,the middle structure is coarse dendrites,the top is cross section dendrites,and the dendritic crystals are?Cu,Ni?phases.The intergranular structure is Cr_0.19Fe_0.7Ni_0.11 and Fe_0.64Ni_0.36;the structure of the?Cu,Ni?-Gd₂O₃ gradient functional composite:the bottom structure is a long-shaped dendritic structure,and the small acicular phase dispersed in the middle The length of the short acicular Cr phase at the top is about20-100?m;TEM analysis shows that the interface between La₂O₃/Gd₂O₃ and Cu matrix is good,which provides a good strengthening effect for Cu matrix.The deformation and stress analysis shows that the maximum offset distance of the bottom layer of?Cu,Ni?-La₂O₃/Gd₂O₃ gradient material decreases with the increase by laser power,while the intermediate layer and the top layer follow the laser power maximum offset distance with the laser power.The residuail stress distribution is in the form of tension on both sides of the middle compression,and the micro-strain is gradually reduced from the bottom layer to the top layer.The tribological properties study shows that the wear rate of?Cu,Ni?-La₂O₃/Gd₂O₃gradient material increases slowly with the increase of friction speed and friction load to80m/s or 50N.The increase rate becomes slow and the trend of friction coefficient change is also consistent;the wear rate of the gradient material increases with the increase of the friction current,and the change of the friction coefficient is consistent;the wear morphology at small currents,the granular spots,the wear morphology under large current,many spherical small droplets Splash morphology,as well as a large number of pores;because the intergranular bond of La₂O₃ gradient material is not as good as Gd₂O₃ gradient material,its friction performance is weaker than Gd₂O₃ gradient material under the same conditions.The mass loss of electroablation of?Cu,Ni?-La₂O₃/Gd₂O₃ gradient samples increases with the increase of current;the macro-morphology of electric ablation samples at different currents exhibits a U-like shape,and the electric ablation cross-sectional area was increased by the current;the micro-morphology of electric ablative is mainly micro-cracks,spherical particles,holes and so on.