摘要
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。
TC4 titanium alloys with different grain sizes were heated from RT to 700 ℃ and compressed uniaxially using a Gleeble-1500 D thermal mechanical simulator.Heating rates of 0,10,30,50,70 ℃/s were used for the heating process.The flow stress of the TC4 titanium alloys during the high temperature compression was investigated under the effects of the current by flow stress curves,SEM and TEM.It is found that the stress can be reduced from around 1000 MPa to below 600 MPa under the application of the current.Dynamic recrystallization occurs at a low current and the stress increases rapidly with the strain at first and reaches a peak value,it then decreases quickly and eventually becomes steady with the further increase of the strain.Dynamic recovery takes place at a high current and dynamic recrystallization is only found at local areas.No stress peak is noticed with a high current and the maximum stress is below 400 MPa.In addition,a higher current can promote a more complete phase transition from β to α.In conclusion,the flow stress of the TC4 titanium alloys can be affected simultaneously by the current,dynamic recrystallization and phase transition and the current can facilitate dynamic recrystallization and phase transition,resulting in the decrease in flow stress.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2017年第6期1572-1577,共6页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51275322)
关键词
流变应力
动态再结晶
相变
TC4钛合金
电塑性效应
flow stress
dynamic recrystallization
phase transition
TC4 titanium alloy
electroplastic effect
