摘要
研究不同铸型对TC4钛合金的微观组织、织构和高温持久性能的影响,利用光学显微镜(OM)、X射线衍射(XRD)、扫描电子显微镜(SEM)和电子背散射衍射(EBSD)等观察与分析TC4钛合金的显微组织与持久性断裂行为。结果表明:不同铸型工艺TC4钛合金的物相均为α相、β相和ω相组成,其中主要物相为α相(约90%)。与石墨型相比,陶瓷型有利于β→α相变,α相高出5.3%,晶粒平均直径大(dmean=37.021μm),晶粒均匀相对稳定,小晶界角少,当α相比例增大时材料强度减小,塑性升高。同时陶瓷型铸造的钛合金试样组织织构强度高、取向明显,织构类型为{1120}<1100>,与y方向呈现约45°的夹角,进一步验证了试样在(100)、(002)、(101)峰强增加的原因,与织构的形成有关;陶瓷型试样的高温持久性优于石墨型,在400、430、460℃下,持久寿命分别提高了1.174%、15.401%、6.998%,均为韧性断裂,其微观形貌为韧窝特征。此外,温度直接影响TC4钛合金的持久寿命,随着温度升高,TC4钛合金的持久寿命逐渐降低。
The effect of different casting moulds on Ti-based alloys such as TC4 is very significant.The microstructures,texture and high-temperature stress rupture of different cast-mould TC4 alloys were investigated by the optical microscopy(OM),scanning electron microscopy(SEM),electron back scattering diffraction(EBSD),and X-ray diffraction(XRD).The persistent fracture behavior of TC4 alloys was studied.The results show that all TC4 alloy samples of different moulds are composed ofαphase,βphase andωphase,andαphase(around 90%in the matrix)is the main phase.Compared with the graphite-moulded TC4 alloy,the ceramic-moulded TC4 alloy is much more beneficial toβ→αphase transition;therefore,the percentage ofαphase is higher(by around 5.3%)and its average grain size is larger(dmean=37.021μm)than those of graphite-moulded TC4 alloys,and distribution of grains is relatively uniform and stable.With the increase ofαphase percentage,the strength of TC4 alloys decreases and the plasticity increases.Simultaneously,the ceramic-moulded TC4 alloy has strong texture and obvious orientation,and the texture type is{1120}<1100>with an angle of 45°along y direction,which further verifies that the texture of samples is related to the enhancement of peaks in(100),(002),(101)directions.The stress rupture of ceramic-moulded TC4 alloy samples at high temperature is better than that of graphite-moulded TC4 alloys.At the temperatures of 400,430,and 460℃,the stress rupture life of the samples which show ductile fracture and dimple appearance in rupture is increased by 1.174%,15.401%,6.998%,respectively.In addition,temperature directly affects the high-temperature stress rupture of TC4 titanium alloy.As the temperature increases,the stress fracture life of TC4 titanium alloy gradually decreases.
作者
刘文杰
宗学文
陈桢
杨雨蒙
杨学东
卢秉恒
Liu Wenjie;Zong Xuewen;Chen Zhen;Yang Yumeng;Yang Xuedong;Lu Bingheng(Xi’an University of Science and Technology,Xi’an 710054,China;Xi’an Jiaotong University,Xi’an 710049,China;AVIC Optoelectronic Technology Co.Ltd,Luoyang 471023,China;The 725th Research Institute of China Shipbuilding Industry Corporation,Luoyang 471026,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2020年第8期2880-2887,共8页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51875452,51804251)
陕西省重点研发计划项目(2018YBXM-G-3-2,2017TSCXL-GY-05-01)。
关键词
TC4钛合金
铸型
微观组织
织构
高温持久性
TC4 titanium alloy
mould
microstructure
texture
high temperature stress rupture
