Study On The Mechanical Properties Of CoNi-Based And W-Based Concentrated Solid Solution Alloys

Concentrated solid solution alloys is a new type of alloy material composed of two or more elements in accordance with equal atomic ratio or approximately equal atomic ratio.Concentrated solid solution alloys with high strength,high hardness,excellent high temperature resistance,corrosion resistance and radiation resistance are considered as ideal candidates for nuclear reactor structural materials,and have broad application prospects in aerospace,shipbuilding and other fields.Concentrated solid solution alloys with both high strength and high ductility can be obtained by appropriate alloy design strategies.Conventional experimental methods for alloy design are costly and time-consuming.In this paper,the effects of different element types on the tensile mechanical properties of single crystal CoNi base concentrated solid solution alloy were studied from the microscopic scale.Study the Hall-Petch and inverse Hall-Petch（HP-IHP）effects of polycrystalline CoNi Fe Al Cu high entropy alloy,and the influence of temperature and Al concentration on its tensile mechanical properties;The deep learning potential（DLP）of WTaTiRe alloy was fitted with the deep learning potential method.The influences of element type,W concentration and strain rate on the mechanical properties of WTaTiRe alloy were studied.The main research contents and results of this paper are as follows:（1）In CoNi-base concentrated solid solution alloys,Fe and Al elements have significant effects on the yield stress of the alloy.The increase of Fe concentration leads to the decrease of yield stress and Young’s modulus.Fe promotes dislocation nucleation and inhibits dislocation proliferation.The strain of phase transition from FCC to BCC face-centered cubic phase（FCC）to body centered cubic phase（BCC）also decreases.The yield stress increases first and then decreases with the increase of Al concentration,and Al inhibits the nucleation of dislocation and promotes the proliferation of dislocation.CoNi Fe Al₆Cu alloy with 60%Al content has a combination of high strength and good plastic deformation ability.There is a yield plateau in the plastic deformation stage,which mainly relies on the motion of dislocation to generate and eliminate lamination and twins.（2）The HP-IHP effect can be observed in polycrystalline CoNi Fe Cu Al high entropy alloy,whose critical average grain size is 18.57 nm.The plastic deformation of the alloy is mainly dominated by dislocation movement at the HP stage,and the plastic deformation is mainly dominated by grain rotation and grain boundary migration at the IHP stage.The lower the temperature,the higher the yield stress of polycrystalline CoNi Fe Cu Al high entropy alloys,at low temperature,the increase of lattice distortion promotes the nucleation and movement of dislocation.The lower the concentration of element Al,the higher the yield stress and Young’s modulus of the alloy.In the alloy with low concentration of element Al,the dislocation first nucleates at the grain boundary,and the movement of dislocation is hindered due to the grain boundary,thus improving the mechanical properties of the alloy.（3）Based on the deep learning algorithm,the DLP potential which can describe the mechanical properties of WTaTiRe alloy is constructed.The influence of Ti,Ta and Re on the mechanical properties of the alloy decreases successively,and the addition of Ti and Ta reduces the yield stress of the alloy,while Re enhances the yield stress of the alloy.The yield stress and Young’s modulus of W_xTaTiRe alloys can be increased with the increase of W concentration,mainly because the phase transition of W_xTaTiRe alloys is inhibited.In the plastic deformation stage,only a small amount of hexagonal close-packed phases（HCP）phase is produced,and dislocation nucleation and movement dominate the plastic deformation stage.The increase of strain rate inhibits the nucleation and proliferation of dislocation,and increases the yield stress of alloy,showing the strengthening of strain rate.Figure 41 Table 3 Reference 125...