Taking a Ti−5Al−5Mo−5V−1Cr−1Fe alloy as exemplary case,the fatigue crack growth sensitivity and fracture features with various tailoredαphase morphologies were thoroughly investigated using fatigue crack growth rate(...Taking a Ti−5Al−5Mo−5V−1Cr−1Fe alloy as exemplary case,the fatigue crack growth sensitivity and fracture features with various tailoredαphase morphologies were thoroughly investigated using fatigue crack growth rate(FCGR)test,optical microscopy(OM)and scanning electron microscopy(SEM).The tailored microstructures by heat treatments include the fine and coarse secondaryαphase,as well as the widmanstatten and basket weave features.The sample with coarse secondaryαphase exhibits better comprehensive properties of good crack propagation resistance(with long Paris regime ranging from 15 to 60 MPa·m1/2),high yield strength(1113 MPa)and ultimate strength(1150 MPa),and good elongation(11.6%).The good crack propagation resistance can be attributed to crack deflection,long secondary crack,and tortuous crack path induced by coarse secondaryαphase.展开更多
This work is aimed to study the effect of boron on wear resistance of Fe-Cr-B alloys containing different boron contents(0 wt%,5 wt%,7 wt%and 9 wt%)from room temperature(RT)to 800°C in order to explore their appl...This work is aimed to study the effect of boron on wear resistance of Fe-Cr-B alloys containing different boron contents(0 wt%,5 wt%,7 wt%and 9 wt%)from room temperature(RT)to 800°C in order to explore their applications as high-temperature wear resistant mechanical parts.Additionally,the wear mechanism of alloys is evaluated.The tribological properties of alloys are systematically studied by using a ball-on-disc tribometer at 10 N and 0.20 m/s from RT to 800°C sliding against Si3N4 ceramic ball.The boron element greatly improves the wear resistance of specimens as compared with that of unreinforced specimen.The friction coefficients of specimens decrease with increasing of testing temperature.The wear rates of Fe-Cr-B alloys decrease firstly and then raise with the increase of boron content.The specific wear rates of specimens with boron are 1/10 of the unreinforced specimen.Fe-21wt%Cr-7wt%B keeps the best tribological properties at high temperature.展开更多
A novel process of electroplating amorphous Fe Cr Ni alloy in chloride aqueous solution with Fe(Ⅱ), Ni(Ⅱ) and Cr(Ⅲ) was reported. Couple plasma atomic emission spectrometry (ICP AES), X ray diffractometry(XRD), sca...A novel process of electroplating amorphous Fe Cr Ni alloy in chloride aqueous solution with Fe(Ⅱ), Ni(Ⅱ) and Cr(Ⅲ) was reported. Couple plasma atomic emission spectrometry (ICP AES), X ray diffractometry(XRD), scanning electronic microscopy(SEM), microhardness test and rapid heating cooling method were adopted to detect the properties of the amorphous Fe Ni Cr deposit, such as composition, crystalline structure, micrograph, hardness, and adherence between deposit and substrate. The effects of the operating parameters on the electrodeposit of the amorphous Fe Ni Cr alloy were discussed in detail. The results show that a 8.7?μm thick mirror like amorphous Fe Ni Cr alloy deposit, with Vicker’s hardness of 530 and composition of 45%~55% Fe, 33%~37% Ni, 9%~23% Cr was obtained by electroplating for 20?min at room temperature(10~30?℃), cathode current 10~16?A/dm 2, pH=1.0~3.0. The XRD patterns show that there only appears a broad hump around 2 θ of 41?°~47?°for the amorphous Fe Ni Cr alloy deposit, while the SEM micrographs show that the deposit contains only a few fine cracks but no pinholes.展开更多
Geometrical Close Packed (GCP) phase in Fe Cr Ni alloy was quantitatively isolated and precisely determined when electrolyzed in 10 % H 3PO 4 electrolyte at a low current density of 5 mA/cm 2 and 22 ℃±1 ℃...Geometrical Close Packed (GCP) phase in Fe Cr Ni alloy was quantitatively isolated and precisely determined when electrolyzed in 10 % H 3PO 4 electrolyte at a low current density of 5 mA/cm 2 and 22 ℃±1 ℃. The transpassive dissolution potential of the alloy matrix under above conditions is about 1 140 mV (SCE), at which GCP phase is in passive state and can be isolated from the alloy.[WT5”HZ〗展开更多
Fe C Cr weld surfacing layers with different compositions and microstructures can be obtained by submerged arc welding with welding wire of the low carbon steel and high alloy bonded flux. With the increase of Cr an...Fe C Cr weld surfacing layers with different compositions and microstructures can be obtained by submerged arc welding with welding wire of the low carbon steel and high alloy bonded flux. With the increase of Cr and C in the layers the microstructures are changed from hypoeutectoid steel, hypereutectoid steel to hypoeutectic iron and hypereutectic iron. When the weld surfacing layers belong to the alloyed cast irons the erosion resistance can be raised with the eutectic increase and the austenite decrease. Good erosion resistance can be obtained when the proportion of the primary carbides is within 10 %. The experimental results lay a foundation to make double metal percussive plates by surfacing wear resistant layers on the substrates of the low carbon steels.展开更多
基金Project(U1867201)supported by the National Natural Science Foundation of ChinaProject supported by State Key Laboratory of Powder Metallurgy,Central South University,China。
文摘Taking a Ti−5Al−5Mo−5V−1Cr−1Fe alloy as exemplary case,the fatigue crack growth sensitivity and fracture features with various tailoredαphase morphologies were thoroughly investigated using fatigue crack growth rate(FCGR)test,optical microscopy(OM)and scanning electron microscopy(SEM).The tailored microstructures by heat treatments include the fine and coarse secondaryαphase,as well as the widmanstatten and basket weave features.The sample with coarse secondaryαphase exhibits better comprehensive properties of good crack propagation resistance(with long Paris regime ranging from 15 to 60 MPa·m1/2),high yield strength(1113 MPa)and ultimate strength(1150 MPa),and good elongation(11.6%).The good crack propagation resistance can be attributed to crack deflection,long secondary crack,and tortuous crack path induced by coarse secondaryαphase.
基金Projects(51775365,51405329) supported by the National Natural Science Foundation of ChinaProject(2015M570239) supported by the China Postdoctoral Science Foundation
文摘This work is aimed to study the effect of boron on wear resistance of Fe-Cr-B alloys containing different boron contents(0 wt%,5 wt%,7 wt%and 9 wt%)from room temperature(RT)to 800°C in order to explore their applications as high-temperature wear resistant mechanical parts.Additionally,the wear mechanism of alloys is evaluated.The tribological properties of alloys are systematically studied by using a ball-on-disc tribometer at 10 N and 0.20 m/s from RT to 800°C sliding against Si3N4 ceramic ball.The boron element greatly improves the wear resistance of specimens as compared with that of unreinforced specimen.The friction coefficients of specimens decrease with increasing of testing temperature.The wear rates of Fe-Cr-B alloys decrease firstly and then raise with the increase of boron content.The specific wear rates of specimens with boron are 1/10 of the unreinforced specimen.Fe-21wt%Cr-7wt%B keeps the best tribological properties at high temperature.
文摘A novel process of electroplating amorphous Fe Cr Ni alloy in chloride aqueous solution with Fe(Ⅱ), Ni(Ⅱ) and Cr(Ⅲ) was reported. Couple plasma atomic emission spectrometry (ICP AES), X ray diffractometry(XRD), scanning electronic microscopy(SEM), microhardness test and rapid heating cooling method were adopted to detect the properties of the amorphous Fe Ni Cr deposit, such as composition, crystalline structure, micrograph, hardness, and adherence between deposit and substrate. The effects of the operating parameters on the electrodeposit of the amorphous Fe Ni Cr alloy were discussed in detail. The results show that a 8.7?μm thick mirror like amorphous Fe Ni Cr alloy deposit, with Vicker’s hardness of 530 and composition of 45%~55% Fe, 33%~37% Ni, 9%~23% Cr was obtained by electroplating for 20?min at room temperature(10~30?℃), cathode current 10~16?A/dm 2, pH=1.0~3.0. The XRD patterns show that there only appears a broad hump around 2 θ of 41?°~47?°for the amorphous Fe Ni Cr alloy deposit, while the SEM micrographs show that the deposit contains only a few fine cracks but no pinholes.
文摘Geometrical Close Packed (GCP) phase in Fe Cr Ni alloy was quantitatively isolated and precisely determined when electrolyzed in 10 % H 3PO 4 electrolyte at a low current density of 5 mA/cm 2 and 22 ℃±1 ℃. The transpassive dissolution potential of the alloy matrix under above conditions is about 1 140 mV (SCE), at which GCP phase is in passive state and can be isolated from the alloy.[WT5”HZ〗
文摘Fe C Cr weld surfacing layers with different compositions and microstructures can be obtained by submerged arc welding with welding wire of the low carbon steel and high alloy bonded flux. With the increase of Cr and C in the layers the microstructures are changed from hypoeutectoid steel, hypereutectoid steel to hypoeutectic iron and hypereutectic iron. When the weld surfacing layers belong to the alloyed cast irons the erosion resistance can be raised with the eutectic increase and the austenite decrease. Good erosion resistance can be obtained when the proportion of the primary carbides is within 10 %. The experimental results lay a foundation to make double metal percussive plates by surfacing wear resistant layers on the substrates of the low carbon steels.