Effect Of Preparation Process On Microstructure And Properties Of Zr-Co-Al Alloy And Deformation Behavior Of Alloy

With the rapid development of science and technology, metal materials as the cornerstone of modern industrial progress, people expect all aspects of its performance are increasingly high. Intermetallic compound based alloy, especially the atomic ratio of Zr-Co alloys, not only have high hardness and strength at room temperature, but there are also certain plastic toughness. The deformation and strengthening mechanisms of Zr-Co alloys remain to be further studied, and engineering application prospects also need to be expanded.In this paper, in order to expand Zr-Co alloy to be used in nuclear reactor shells, bars, plates and pseudo-ingots with three components such as Zr49.5Co49.sAl1, Zr49Co49Al2 and Zr48.5Co48.5Al3 were prepared by water-cooled copper mold suction casting rapid solidification. Subsequently, Zr49Co49Al2 plates were successfully prepared by ordinary solidification casting and different subsequent mechanical heat treatments. Finally, the mechanical properties of the ordinary casting sheets were examined in the range from room temperature to 500℃. X-ray diffraction analyzer (XRD), X-ray photoelectron spectroscopy analyzer (XPS), optical microscope (OM) and scanning electron microscopy (SEM) were used to analysis the microstructure of Zr-Co-Al alloys. Differential scanning calorimetry (DSC) was used to test the thermodynamic characteristics of alloys. The Vickers hardness and mechanical universal testing machine were used to measure mechanical properties of Zr-Co-Al alloys. The effects on the microstructures and properties of Zr-Co alloy with low Al content prepared by rapidly solidification were studied through a series of experiments, explored the processes such as ordinary casting combined with different mechanical and heat treatments to obtain uniform defect-free Zr-Co-Al alloys, also probe the comparison strengthen and deformation mechanism in high-temperature environments. Researchs indicate that:Zr49Co49Al2 is a ingredient which has the best mechanical properties in rapidly solidified rods, plates and pseudo ingots respectively, which closely relate to its smaller grain size and uniform dispersion of the second phase grains. The compression strength and compression rates of Zr4yCo49Al2 sheets were 2891MPa and 62.6%. Zr49Co49Al2 alloys prepared by ordinary solidification casting could finish the composition ratio to meet the design requirements, grain sizes grow up and compositions become uniform after diffusion annealing. The Zr-Co-Al alloys with the smallest average grain size and uniform composition after the 30% reduction hot rolling process have the best performance, B33 phase appears with a small amount at the same time, ultimate The tensile and compression rates are, respectively,2.4% and 31.0% at room temperature. Fracture mechanisms of Zr49Co49Al2 alloys at different temperatures are all intergranular brittle fractures, fine grain toughening play an important role, B33 phases on the base B2-CoZr maintain the plastic materials with a high level strength. There is a certain hardening phenomenon during deformation. Creep mechanisms play a role when alloys deform at high temperatures, plasticity and toughness will increase but the strength become lower. A new phase Al2CoZr6 generate and disperse at 500℃, as a result to impact on material properties by second phase strengthening.