脉冲强磁场处理对TC4钛合金显微组织及力学性能的影响

Effect of high pulsed magnetic field on microstructure and mechanical properties of TC4 titanium alloy

研究在脉冲强磁场处理条件下磁感应强度(B=2T、3T和4T)对TC4钛合金材料显微组织和力学性能的影响。结果表明:随着B值从2T增加到4T,α相体积分数从49%增加到59%,表明磁场诱发了从β到α的相变。经过磁场处理后,位错密度增加,当B=3T时,位错密度达到最大值,较未处理试样增加了4.8倍;当B=4T时,位错密度有所减小,这是由于磁致塑性效应和位错堆积效应共同作用的结果。经过磁场处理后,合金的强度提高了,当B=3T时,合金强度最高达到1330 MPa,较未处理试样的1236 MPa提高7.6%;当B=4T时,合金强度为1265 MPa,增幅2.3%,合金伸长率为15.66%,较处理前样品的伸长率提高4.8%,实现材料强度和塑性的同步提高,这与位错强化机制和α相的数量、分布和形貌有关。

The effects of magnetic induced intensity （B=2T, 3T and 4T） on the microstmcture and mechanical properties of TC4 titanium alloy in the condition of high pulsed magnetic field （HPMF） were investigated. The results show that the volume fraction of a phase increases from 49% to 59% when B increases from 2T to 4T, which demonstrates that the HPMF can induce the phase transformation from β to α phase. After the HPME treatment, the dislocation density increases. The dislocation density reaches a maximum when B=3T, which is added by 4.8 times compared to that without HPMF treatment. When B=4T, the dislocation density decreases a bit. The phenomenon is ascribed to the combined effects of magnetoplasticity and dislocation piles-up. Meanwhile, the tensile strength increases due to HPMF treatment. When B=3T, the tensile strength is 1330 MPa, which increases by 7.6% compared to that without treatment. When B=4T, the tensile strength and amplification are 1265 MPa and 2.3%, respectively. And the elongation is 15.66% which increases by 4.8% compared to that without treatment. Therefore, the strength and elongation increases synchronously, which is the result of dislocation strengthening mechanism and the amount, distribution and morphology of a phase.