By metallographic test, SEM, TEM and energy spectrum, the microstructure and properties of Cu 15Ni 8Sn 0.4Si alloy were studied. The results show that the added Si combines with Ni and forms Ni 3Si and Ni 2Si phases. ...By metallographic test, SEM, TEM and energy spectrum, the microstructure and properties of Cu 15Ni 8Sn 0.4Si alloy were studied. The results show that the added Si combines with Ni and forms Ni 3Si and Ni 2Si phases. During ageing at 380 ℃, the precipitation of Ni 2Si phase suppresses discontinuous precipitation to some degree. After adding Si, the conductivity and hardness of Cu 15Ni 8Sn alloy are increased to some degree.展开更多
The effect of precipitation on the internal friction(IF)of AZ91 magnesium alloy was investigated by using X-ray diffraction(XRD)analysis,scanning electron microscope(SEM)observation,and dynamic mechanical analysis(DMA...The effect of precipitation on the internal friction(IF)of AZ91 magnesium alloy was investigated by using X-ray diffraction(XRD)analysis,scanning electron microscope(SEM)observation,and dynamic mechanical analysis(DMA).Six different states of alloy were prepared by applying different heat treatment processes:as-cast,in-complete solid solution,complete solid solution,micro-precipitation,continuous precipitation and continuous-discontinuous precipitation.It was found that the internal friction of in-completely solid-solutionized,completely solid-solutionized and micro-precipitated specimens showed a similar characteristic,and the grain boundary relaxation is completed depressed due to the Al atoms supersaturated in theα-Mg solution.However,a thermal relaxation internal friction peak was observed for continuously precipitated and continuously-discontinuously precipitated specimens at around 438 K and frequency of about 1 Hz,which was attributed to the grain boundaries relaxation.Furthermore,it was found that the relaxation of theβ-Mg17Al12/α-Mg phase interfaces should give its contribution to the background internal friction in the as-cast,continuously precipitated and continuously-discontinuously precipitated specimens.展开更多
文摘By metallographic test, SEM, TEM and energy spectrum, the microstructure and properties of Cu 15Ni 8Sn 0.4Si alloy were studied. The results show that the added Si combines with Ni and forms Ni 3Si and Ni 2Si phases. During ageing at 380 ℃, the precipitation of Ni 2Si phase suppresses discontinuous precipitation to some degree. After adding Si, the conductivity and hardness of Cu 15Ni 8Sn alloy are increased to some degree.
文摘The effect of precipitation on the internal friction(IF)of AZ91 magnesium alloy was investigated by using X-ray diffraction(XRD)analysis,scanning electron microscope(SEM)observation,and dynamic mechanical analysis(DMA).Six different states of alloy were prepared by applying different heat treatment processes:as-cast,in-complete solid solution,complete solid solution,micro-precipitation,continuous precipitation and continuous-discontinuous precipitation.It was found that the internal friction of in-completely solid-solutionized,completely solid-solutionized and micro-precipitated specimens showed a similar characteristic,and the grain boundary relaxation is completed depressed due to the Al atoms supersaturated in theα-Mg solution.However,a thermal relaxation internal friction peak was observed for continuously precipitated and continuously-discontinuously precipitated specimens at around 438 K and frequency of about 1 Hz,which was attributed to the grain boundaries relaxation.Furthermore,it was found that the relaxation of theβ-Mg17Al12/α-Mg phase interfaces should give its contribution to the background internal friction in the as-cast,continuously precipitated and continuously-discontinuously precipitated specimens.
