Microstructure Evolution And Mechanical Properties Of Dy Alloyed NiAl-xV Based Alloys

As a high-end material,superalloys are widely used in many fields,especially in th e aerospace and energy power fields.NiAl materials have excellent physical and chemical properties such as high melting point,high temperature oxidation resistance,corrosion r esistance and low density,and have the potential to become new high temperature mater ials.However,its room temperature toughness and plasticity are poor,which becomes a c onstraint on the application of the alloy.The research group added V to the foundation o f NiAl,and its high temperature compression,room temperature compression and fractur e toughness were greatly improved.Therefore,Dy was added to explore its microstructu re evolution and mechanical properties.The solidification microstructure and mechanical properties of hypoeutectic NiAl-32 V,eutectic NiAl-39 V and hypereutectic NiAl-43 V alloys with different Dy contents were studied.Refining NiAl-32V(0,0.05,0.1,0.3,0.5 wt%),NiAl-39V(0,0.05,0.1,0.3,0.5,1wt%),NiAl-43V(0,0.05,0.1,0.3,0.5,1wt%)alloy by vacuum arc furnace,,to e xplore the effect of rare earth element Dy on the microstructure and mechanical properti es of NiAl-V matrix.The results show that the amount and morphology of the primary phase NiAl incre ase and the number of eutectic groups increase when the rare earth element Dy is adde d to the NiAl-32 V alloy.After the addition of NiAl-39 V to the Dy element,the numbe r of eutectic groups increases,and the eutectic cell boundary The V phase and the NiAl phase become coarse,and the unit cell is refined.The primary phase precipitates with t he increase of the content.After the addition of NiAl-43 V to the Dy element,the dendr ites and grains are refined and the number is increase.It can be seen from room tempe rature compression and three-point bending that the strength of room temperature decreas es when rare earth Dy is added to NiAl-32 V.However,after adding appropriate amount of Dy to NiAl-39 V and NiAl-43 V,the room temperature strength is significantly improved,and the fracture toughness is slightly improved compared with that before the additi on of rare earth..It can be seen from high temperature compression that an appropriate amount of Dy is added to NiAl-32 V,NiAl-39 V and NiAl-43 V,and the activation ener gy of NiAl-39V-0.05 Dy and NiAl-43V-0.05 Dy is higher than that of NiAl-39 V and NiA l.-43 V.It shows that the addition of Dy improves the high temperature strength of Ni Al-V alloy,but in room temperature compression,the room temperature defects of NiAl-39 V and NiAl-43 V alloy are improved,and the room temperature compressive strength of NiAl-32 V alloy is reduced.When Dy is added to the eutectic and hypereutectic alloy,the room temperature fracture toughness is also improved slightly.