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采用Gleeble-1500D热-力学模拟机,将不同晶粒尺寸的TC4试样分别以0、10、30、50和70℃/s的升温速度加热至700℃进行单向压缩并得到流变应力曲线图,结合SEM、TEM等研究了电流作用下TC4钛合金高温压缩过程中流变应力的变化及影响因素。结果表明,无电流时流变应力超过1000 MPa,在电流作用下可降至600 MPa以下。小电流下TC4试样发生动态再结晶,应力随应变快速增大到应力峰值,后又快速下降至稳定状态;大电流下发生动态回复,局部有动态再结晶,无应力峰值,应力最大值低于400 MPa,且电流越大,β相转变为α相的相变越完全。分析认为,TC4钛合金的流变应力受电流大小、动态再结晶和相变的共同影响,电流促进动态再结晶和相变并降低流变应力。
Using the Gleeble-1500D thermo-mechanical simulator, the TC4 samples with different grain sizes were heated to 700 ℃ at 0, 10, 30, 50 and 70 ℃ / s respectively for one-way compression and the flow stress curves Figure, combined with SEM, TEM and other studies under the current TC4 titanium alloy flow stress during high temperature stress changes and influencing factors. The results show that the flow stress in the absence of current exceeds 1000 MPa and can drop below 600 MPa under the current. The dynamic recrystallization of TC4 sample occurs at low current, the stress increases rapidly to the peak value of stress with strain, and then rapidly drops to the steady state. The dynamic recovery occurs under high current, and there is dynamic recrystallization locally with no stress peak and the maximum stress is low At 400 MPa, the larger the current, the more complete the phase transition from β phase to α phase. The analysis shows that the flow stress of TC4 titanium alloy is affected by the current size, dynamic recrystallization and phase transformation. The current promotes the dynamic recrystallization and phase transformation and reduces the flow stress.