Study On The Preparation And Heat Treatment Of Ni-Mn-In-(Cu)ribbons

In this paper,Ni-Mn-In ribbons with two different compositions(Ni50Mn35In15 and Ni50Mn36In14)were prepared by vacuum single-roll quick-cooling stripping method,which were named NMI15 and NMI14 respectively.After doping,a quaternary alloy ribbon with a composition of Ni50Mn32In15Cu3(NMIC3)was obtained.The structure,martensite transformation and thermal hysteresis of the ribbons under different preparation parameters were investigated,and the structure,martensite transformation,thermal hysteresis and phase transformation of the ribbons after heat treatment in different processes(different temperatures)The changes in latent heat were investigated.NMI15,NMI14,and NMIC3 alloy ribbonss with good continuity were successfully prepared by changing the process parameters such as heating power,copper wheel speed,and injection air pressure during the preparation process of the rapid cooling stripping method.Scanning electron microscopy(SEM)was used to observe the morphology of different fibers.Different scanning calorimetry(DSC),X-ray diffraction analysis(XRD),energy spectrum analysis(EDS)and other methods were used to analyze the ribbonss in different preparation states.Composition,phase and phase transition temperature.The comparison shows that when the heating power is 11 k W,the copper wheel speed is 900 rpm,the injection pressure is 0.1MPa,the ribbons has a better preparation state.The analysis of DSC,SEM,EDS,XRD and other analytical methods was carried out to analyze the phase transition temperature,morphology,composition and substance equality of different prepared ribbonss.The phase transition temperature of the three alloy prepared ribbonss is lower than that of the alloy ingot.The heating power mainly affects the content of Mn element in the ribbonss,resulting in different phase transition temperatures of the ribbonss under different heating powers.The speed of the copper wheel has little effect on the composition of the ribbons,but because the phase transition temperature is very sensitive to the alloy composition,it also causes the phase transition temperature to change.At the same time,the copper wheel speed and heating power will also affect the length and thickness of the thin belt.The higher the copper wheel speed,the greater the centrifugal force when the thin belt is thrown out,the shorter the length of the thin belt,and the smaller the thickness of the thin belt.The heating power mainly affects the viscosity of the molten alloy,resulting in the difference between the length and thickness of the ribbons.Under the same parameters,the thin ribbon quality of NMIC3 thin ribbon is the best,and the thin ribbon quality of NMI15 is the worst.Due to the internal stress and defects in the prepared ribbons,the resistance to martensite transformation will increase,so the hysteresis of the thin phase transformation will increase,and it will also cause the latent heat of the thin phase transformation to decrease.The ribbons were heat-treated at different temperatures,and the phase transition temperature,composition,and material equality of the ribbonss in different heat treatments were analyzed using DSC,EDS,XRD and other analytical methods.Due to the release of internal stress and the reduction of defects in the ribbons,the phase transition temperature of the three alloy ribbonss has increased,but it does not increase with the increase of the heat treatment temperature.At the same time,the room temperature phase structure of the NMI14 and NMI15 heat treated ribbonss at different temperatures has not changed,while the NMIC3 alloy strip has a matrix structure at 873 K and 973 K,and becomes a mixed phase of the matrix phase and martensite at 1073 and 1173 K.organization.After the heat treatment,the thermal hysteresis of the phase transition of the three alloy ribbons is reduced.At the same time,the higher the heat treatment temperature,the lower the thermal hysteresis of the phase transition.Rise.