Study On Creep And Fretting Wear Properties Of FeCrAl Alloy Under Different Annealing Processes

In this paper,the heat treatment process of smelted-forged-rolled FeCrAl-Nb fullsize alloy thin-walled tubes was studied.By comparing the alloy microstructure under different thermal processes,the recrystallization behavior of thin-walled tubes of FeCrAl alloy was studied,and the recrystallization kinetics of the alloy were analyzed in detail,and the optimal heat treatment process parameters(annealing at 800 °C for 1h)were obtained.At the same time,the effect of temperature on the tensile properties of Thin-walled Pipes of FeCrAl alloy and the evolution of fracture mechanism with temperature were studied by simulating the working temperature(400 °C),and the effect of temperature on the tensile properties of Thin-walled Pipes of FeCrAl Alloy and the evolution of fracture mechanism with temperature were studied in detail.The effect of creep stress(220 MPa,190 MPa,and 160 MPa)on creep properties of FeCrAl alloy clad tubes at 400 °C was studied.The steady-state creep rate of the alloy was studied,creep tissue,post-creep texture,and precipitated phase particles.Finally,the effect of the annealing process on the fretting wear properties of the alloy was studied.The specific research contents and conclusions are as follows:(1)The effects of different annealing processes on the micromorphology,texture growth direction,and mechanical properties of FeCrAl alloy were studied.As the annealing temperature increases,the alloy recovers and recrystallizes.The addition of Ta causes more second-phase precipitation and the nailing of Fe2Mo4 C and Fe2 Nb to form more grain boundaries,hindering the growth and refinement of grains.The high temperature stable second phase provides sufficient high-temperature strength for the alloy.(2)The effect of temperature on the axial tensile properties,fracture form,and fracture mechanism of FeCrAl alloy was studied.With the increase in tensile temperature,the fracture of the alloy reasons for the transition from tough and brittle fracture to ductile fracture.It is proved that the strength/plasticity of the fe Cr Al alloy decreases due to phase precipitation when stretched at 400°C,and it is preliminarily proved that it is caused by the precipitation of the α ? phase.The effect of stress on the creep performance of FeCrAl alloy at 400°C was studied,and the results showed that the steady-state creep rate of FeCrAl was much lower than that of zirconium alloy,and the creep mechanism of high stress at a temperature below 0.3 times the melting point was mainly dislocation creep and contained grain boundary creep and vacancy creep.(3)The fretting wear test of FeCrAl alloy in a dry state was carried out.The results show that with the increase of annealing temperature,the more serious the transfer of alloying elements,the wear depth and wear area increase,and the wear machine reason abrasive wear changes to oxidative wear.The effect of aging time on alloy wear performance is studied,and the results show that with the increase of aging time,the wear of the alloy increases first and then decreases,and the wear mechanism is changed from abrasive wear to oxidative wear to abrasive wear due to the ordering of the alloy and the curing of the precipitation phase.