The two-pass equal channel angular extrusion (ECAE) process was introduced into strain-induced melt activation (SIMA) to predeform a ZK60 alloy with rare earth (RE) addition. Microstructure evolution of ECAE-formed ZK...The two-pass equal channel angular extrusion (ECAE) process was introduced into strain-induced melt activation (SIMA) to predeform a ZK60 alloy with rare earth (RE) addition. Microstructure evolution of ECAE-formed ZK60+RE alloy during reheating was investigated. Furthermore, tensile properties of thixoforged components were determined. The results show that the SIMA process can produce ideal microstructures, and spheroidized solid particles with little entrapped liquid can be obtained. With prolonging holding time, the size of solid particles increases and the degree of spheroidization is improved. The tensile properties of the thixoforged ZK60+RE samples are close to those of two-pass ECAE-formed samples.展开更多
The influence of equal channel angular extrusion preheating on the microstructure of NiTi was examined. Temperatures under non-isothermal condition is 750, 850 and 950 ℃, and ram speed was 25 mm·s^(-1). The micr...The influence of equal channel angular extrusion preheating on the microstructure of NiTi was examined. Temperatures under non-isothermal condition is 750, 850 and 950 ℃, and ram speed was 25 mm·s^(-1). The micrographs showed that processing by each of the three temperatures via ECAE can refine the initial coarse grains of NiTi (as-received) after the first pass, and the developments of microstructure were quite different under different hot-working conditions. The influence of ECAE preheating (including temperature and time) on the microstructure of nickel-titanium was analyzed.展开更多
The influence of rare earth Y on the microstructure and mechanical properties of Al-Zr alloy produced by dynamic ECAE was studied by OLYMPUS-BX51M optical microscope(OM),S4800 energy disperse spectroscopy(EDS)and SANS...The influence of rare earth Y on the microstructure and mechanical properties of Al-Zr alloy produced by dynamic ECAE was studied by OLYMPUS-BX51M optical microscope(OM),S4800 energy disperse spectroscopy(EDS)and SANS CMT5105 electronic universal material testing machine,and the corresponding equivalent conductivity was also investigated by using QJ48 DC electric bridge.The results show that the tensile strength of Al-Zr conductor first increases and then decreases with the increase of the aging time and temperature,and the highest tensile value can be obtained under the aging temperature of 160°C for 4 h.The ductility and the resistivity of the Al-Zr alloy have inverse proportion to the aging time.The rare earth Y has significantly improved the electrical and mechanical properties of Al-0.3%Zr heat-resistant alloy.In this study,the tensile strength and the elongation of the Al-0.3%Zr-0.2%Y alloy,after aging treatment at 220°C for 14 h,are about 278.49 MPa and 6.7%,respectively,and the equivalent conductivity is about 59.6 IACS.Hence the synthetical properties of the Y-containing alloy are significantly improved compared with traditional Al-0.3%Zr alloy.展开更多
In this present work, a study regarding the change in the mechanical properties and in the microstructure of the aluminium alloy AA1050 is made after being processed by severe plastic deformation (SPD) with Equal Chan...In this present work, a study regarding the change in the mechanical properties and in the microstructure of the aluminium alloy AA1050 is made after being processed by severe plastic deformation (SPD) with Equal Channel Angular Extrusion (ECAE). Optical and scanning electron microscopy techniques will be employed in order to determine the evolution of the microstructure after different thermal treatments, subsequent to the severe plastic deformation process. This present work involves a profound study on the change in the mechanical properties for an alloy which has a very low value of strain hardening at room temperature. With this, it is demonstrated that it is possible to improve its mechanical properties significantly with an adequate combination of ECAE processing and thermal treatments.展开更多
文摘The two-pass equal channel angular extrusion (ECAE) process was introduced into strain-induced melt activation (SIMA) to predeform a ZK60 alloy with rare earth (RE) addition. Microstructure evolution of ECAE-formed ZK60+RE alloy during reheating was investigated. Furthermore, tensile properties of thixoforged components were determined. The results show that the SIMA process can produce ideal microstructures, and spheroidized solid particles with little entrapped liquid can be obtained. With prolonging holding time, the size of solid particles increases and the degree of spheroidization is improved. The tensile properties of the thixoforged ZK60+RE samples are close to those of two-pass ECAE-formed samples.
文摘The influence of equal channel angular extrusion preheating on the microstructure of NiTi was examined. Temperatures under non-isothermal condition is 750, 850 and 950 ℃, and ram speed was 25 mm·s^(-1). The micrographs showed that processing by each of the three temperatures via ECAE can refine the initial coarse grains of NiTi (as-received) after the first pass, and the developments of microstructure were quite different under different hot-working conditions. The influence of ECAE preheating (including temperature and time) on the microstructure of nickel-titanium was analyzed.
基金Funded by the Science and Research Program of Chongqing Municipal Education Commission(No.KJZD-M201801401)Talent Start Fund of Yangtze Normal University(No.2018KYQD006)
文摘The influence of rare earth Y on the microstructure and mechanical properties of Al-Zr alloy produced by dynamic ECAE was studied by OLYMPUS-BX51M optical microscope(OM),S4800 energy disperse spectroscopy(EDS)and SANS CMT5105 electronic universal material testing machine,and the corresponding equivalent conductivity was also investigated by using QJ48 DC electric bridge.The results show that the tensile strength of Al-Zr conductor first increases and then decreases with the increase of the aging time and temperature,and the highest tensile value can be obtained under the aging temperature of 160°C for 4 h.The ductility and the resistivity of the Al-Zr alloy have inverse proportion to the aging time.The rare earth Y has significantly improved the electrical and mechanical properties of Al-0.3%Zr heat-resistant alloy.In this study,the tensile strength and the elongation of the Al-0.3%Zr-0.2%Y alloy,after aging treatment at 220°C for 14 h,are about 278.49 MPa and 6.7%,respectively,and the equivalent conductivity is about 59.6 IACS.Hence the synthetical properties of the Y-containing alloy are significantly improved compared with traditional Al-0.3%Zr alloy.
文摘In this present work, a study regarding the change in the mechanical properties and in the microstructure of the aluminium alloy AA1050 is made after being processed by severe plastic deformation (SPD) with Equal Channel Angular Extrusion (ECAE). Optical and scanning electron microscopy techniques will be employed in order to determine the evolution of the microstructure after different thermal treatments, subsequent to the severe plastic deformation process. This present work involves a profound study on the change in the mechanical properties for an alloy which has a very low value of strain hardening at room temperature. With this, it is demonstrated that it is possible to improve its mechanical properties significantly with an adequate combination of ECAE processing and thermal treatments.
