The influence of ageing time on microstructure and mechanical properties of low-cost beta （LCB） titanium alloy with a chemical composition of Ti-6.6Mo-4.5Fe-1.5Al was investigated. The correlation between microstruc...The influence of ageing time on microstructure and mechanical properties of low-cost beta （LCB） titanium alloy with a chemical composition of Ti-6.6Mo-4.5Fe-1.5Al was investigated. The correlation between microstructure and fatigue crack initiation and growth was also studied. Increasing ageing time tended to increase the volume fraction of the secondary α-precipitates, β-grain size and partial spheroidization of primary α-phase. The maximum tensile strength （1565 MPa） and fatigue limit （750 MPa） were obtained for the samples aged at 500 °C for 0.5 h, while the minimum ones of 1515 MPa and 625 MPa, respectively, were reported for the samples aged at 500 °C for 4 h. The samples aged at 500 °C for 4 h showed a transgranular fracture mode. However, the samples aged at 500 °C for 0.5 h revealed a mixture fracture mode of transgranular and intergranular. The formed cracks on the outer surface of the fatigue samples were found to propagate through the β-grains connecting the primary α-particles existing at the β-grain boundaries.展开更多
In the view of crystallization activation energy of amorphous alloy, the mechanism of coarse grain in annealed Sm 5Fe 80Cu 1Si 5B 3C 2.5Zr 3.5 amorphous alloy was analyzed. It reveals the effect of preannealing on the...In the view of crystallization activation energy of amorphous alloy, the mechanism of coarse grain in annealed Sm 5Fe 80Cu 1Si 5B 3C 2.5Zr 3.5 amorphous alloy was analyzed. It reveals the effect of preannealing on the process crystallization. The results show that preannealing can be used to change the crystallization behavior of the α-Fe phase in the Sm 5Fe 80Cu 1Si 5B 3C 2.5Zr 3.5 amorphous alloy, which is helpful for forming α-Fe phase grains; and it is not large for Sm 2Fe 17C x phase.展开更多
文摘The influence of ageing time on microstructure and mechanical properties of low-cost beta （LCB） titanium alloy with a chemical composition of Ti-6.6Mo-4.5Fe-1.5Al was investigated. The correlation between microstructure and fatigue crack initiation and growth was also studied. Increasing ageing time tended to increase the volume fraction of the secondary α-precipitates, β-grain size and partial spheroidization of primary α-phase. The maximum tensile strength （1565 MPa） and fatigue limit （750 MPa） were obtained for the samples aged at 500 °C for 0.5 h, while the minimum ones of 1515 MPa and 625 MPa, respectively, were reported for the samples aged at 500 °C for 4 h. The samples aged at 500 °C for 4 h showed a transgranular fracture mode. However, the samples aged at 500 °C for 0.5 h revealed a mixture fracture mode of transgranular and intergranular. The formed cracks on the outer surface of the fatigue samples were found to propagate through the β-grains connecting the primary α-particles existing at the β-grain boundaries.
文摘In the view of crystallization activation energy of amorphous alloy, the mechanism of coarse grain in annealed Sm 5Fe 80Cu 1Si 5B 3C 2.5Zr 3.5 amorphous alloy was analyzed. It reveals the effect of preannealing on the process crystallization. The results show that preannealing can be used to change the crystallization behavior of the α-Fe phase in the Sm 5Fe 80Cu 1Si 5B 3C 2.5Zr 3.5 amorphous alloy, which is helpful for forming α-Fe phase grains; and it is not large for Sm 2Fe 17C x phase.
