Mechanical and magnetic properties as well as their relationship in the reduced activation martensitic （RAM） steel were investigated in the temperature range from -90℃ to 20℃. Charpy impact tests show that the duc...Mechanical and magnetic properties as well as their relationship in the reduced activation martensitic （RAM） steel were investigated in the temperature range from -90℃ to 20℃. Charpy impact tests show that the ductile-to-brittle transition temperature （DBTT） of the RAM steel is about -60℃. Low-temperature tensile tests show that the yield strength, ultimate tensile strength and total elongation values increase as temperature decreases, indicating that the strength and plasticity below the DBTT are higher than those above the DBTT. The coercive field （Hc） in the scale of logarithm decreases linearly with the increasing temperature and the absolute value of the slope of InHc versus temperature above the DBTT is obviously larger than that below the DBTT, also confirmed in the T91 steel. The results indicate that the non-destructive magnetic measurement is a promising candidate method for the DBTT detection of ferromagnetic steels.展开更多
Surface roughness is commonly used to characterize material microstructure during processing,and accurate measurement of surface roughness is the premise and foundation of machining.Therefore,online non-destructive me...Surface roughness is commonly used to characterize material microstructure during processing,and accurate measurement of surface roughness is the premise and foundation of machining.Therefore,online non-destructive measurement of surface roughness based on the laser speckle method has become a hot issue in recent research.The improvements in surface roughness measurements based on the laser speckle method are systematically reviewed.Theory of speckle formation is introduced.The statistical properties of the speckle patterns including first-order statistical properties and second-order statistical properties are directly related to surface roughness.Surface roughness measurements based on the laser speckle method are roughly divided into the speckle contrast method,speckle correlation method,and fractal method.The three methods are described in detail,and an extensive comparison among all the methods is presented.The recent progresses and application of surface roughness measurements are reviewed.Finally,surface roughness measurements based on the laser speckle method are prospected and summarized.展开更多
文摘Mechanical and magnetic properties as well as their relationship in the reduced activation martensitic （RAM） steel were investigated in the temperature range from -90℃ to 20℃. Charpy impact tests show that the ductile-to-brittle transition temperature （DBTT） of the RAM steel is about -60℃. Low-temperature tensile tests show that the yield strength, ultimate tensile strength and total elongation values increase as temperature decreases, indicating that the strength and plasticity below the DBTT are higher than those above the DBTT. The coercive field （Hc） in the scale of logarithm decreases linearly with the increasing temperature and the absolute value of the slope of InHc versus temperature above the DBTT is obviously larger than that below the DBTT, also confirmed in the T91 steel. The results indicate that the non-destructive magnetic measurement is a promising candidate method for the DBTT detection of ferromagnetic steels.
基金This work was supported by the National Key Research and Development Plan(Grant No.2020YFB1713600)Xinjiang Science and Technology Assistance Program(Grant No.2021E02060)+2 种基金the Fundamental Research Funds for the Central Universities(Grant No.FRF-TP-20-105A1 and FRF-TP-19-002A3)National Natural Science Foundation of China(Grant No.51975043)the China Postdoctoral Science Foundation(Grant No.2021M69035)。
文摘Surface roughness is commonly used to characterize material microstructure during processing,and accurate measurement of surface roughness is the premise and foundation of machining.Therefore,online non-destructive measurement of surface roughness based on the laser speckle method has become a hot issue in recent research.The improvements in surface roughness measurements based on the laser speckle method are systematically reviewed.Theory of speckle formation is introduced.The statistical properties of the speckle patterns including first-order statistical properties and second-order statistical properties are directly related to surface roughness.Surface roughness measurements based on the laser speckle method are roughly divided into the speckle contrast method,speckle correlation method,and fractal method.The three methods are described in detail,and an extensive comparison among all the methods is presented.The recent progresses and application of surface roughness measurements are reviewed.Finally,surface roughness measurements based on the laser speckle method are prospected and summarized.
