Studay On Directional Emissivity Of Ti-6Al-4V Alloy And Its Application Of Radiation Temperature Measurement

Emissivity is one of the most basic physical quantities of thermal radiation,which has the ability to characterize the amount of thermal radiation outward from an object.It has very important application value in military fields,aerospace,industrial production,radiation temperature measurement and other fields.Material spectral emissivity with a lot of information can be extracted and applied in many aspects,For example,the spectral emissivity of the measured material has the large error in the process of radiation temperature measurement could directly results in low accuracy of the radiation temperature measurement,moreover,the spectral emissivity of the material is related to many factors,such as measurement angle,roughness,wavelength,temperature,the degree of oxidation.Therefore,it is extremely difficult to accurately measure.Therefore,emissivity is a physical quantity that is extremely difficult to measure accurately.Accurate measurement of the emissivity of the material is the top priority under different conditions.Compared to the normal emissivity,spectral emissivity has some characteristics with angle,which can be applied to the direction of radiation temperature measurement by studied the largest emissivity value at a certain measurement angle.However,there are few domestic measuring instruments and the production of equipment parts is more difficult.Therefore,there was fewer accurate data on material emissivity.Based on this,the article described the directional emissivity measurement device built by the laboratory based on Fourier infrared spectrometer in detail,the directional emissivity of Ti–6Al–4V alloy was systematically measured at different measurement angles,temperatures,wavelengths,roughness,and degree of oxidation.The research content is as follows:1.The background and application value of Ti-6Al-4V alloy materials was introduced,and the research status of the emissivity of Ti-6Al-4V alloy materials was investigated at home and abroad.It is found that the emissivity of Ti—6Al–4V alloy material was more measured in the normal direction,and the radiation characteristics of this material was less studied systematically.2.the directional emissivity measuring devices by the laboratory was set up based on the energy contrast method.The instrument mainly includes: a vacuum sample furnace,a black body furnace,a parabolic mirror,an electric rotating stage,a Fourier infrared spectrometer,and a data acquisition system.The measuring principle and experimental steps of the instrument was introduced.3.In this paper,the directional emissivity of Ti–6Al–4V alloy at 0-84° was measured by Fourier transform infrared spectroscopy at the temperature range of 573-953 K and the wavelength range of 3-20 μm.The influence of direction on spectral emissivity was systematically studied.4.The effects of roughness on the directional spectral emissivity of Ti-6Al-4V alloy at different measurement angles was measured at 723 K.The results show that the emissivity of Ti-6Al-4V alloy increased with the increased of the roughness.As the angle increases,it can be seen that the emissivity of Ti–6Al–4V alloy shows the characteristics similar with insulator in the angle range of 0-84° when the measurement wavelength is less than 10.3μm,and shows characteristics more similar with metal when the wavelength exceed 10.3μm.5.used the above to obtain the change in the emissivity of the Ti–6Al–4V alloy at 70 °,the emissivity function of the material at this angle was found,and the radiation signal and multi-wavelength algorithm used to calculate the temperature and emissivity under different emissivity functions.By compared with the experimentally measured temperature and emissivity data.Immediately after,the emissivity data of AL7075 alloy and basic copper carbonate were studied,and the measured emissivity data were fitted,and the bivariable emissivity function between wavelength,temperature,and emissivity was obtained.The emissivity function corrected the results of radiation temperature measurement to obtain the true temperature of the object surface.