摘要
采用电子束物理气相沉积(EB-PVD)技术,成功制备了尺寸为150mm×100mm的TiAl基合金薄板,并利用光学显微镜(OM)、扫描电子显微镜(SEM)和X射线衍射(XRD)等测试手段,对真空退火或热压前后试样的显微形貌、物相组成等进行了分析。结果表明,蒸镀态TiAl基合金薄板由γ相、α2相和τ相组成,成分呈梯度变化,内部自然分层,显微组织结构为柱状晶;经1000℃,16h的真空退火处理后,柱状晶和τ相消失,α2相含量显著减少,成分趋于均匀化;而经1250℃,1h的真空热压处理后,材料致密度得到明显提高。TiAl基合金薄板经真空退火或热压处理前后,断裂方式由沿晶断裂转变为解理断裂和沿晶断裂的混合断裂方式。
TiAl-based alloys sheet of 150 mm ×100 mm in size were successfully fabricated by electron beam-physical vapor deposition (EB-PVD) process. The phase composition and microscopic morphology were analyzed by optical microscope (OM), scanning electron microscope (SEM) and X-ray diffractometer (XRD) for the as-deposited, as-annealed or as-pressed samples, respectively. The results show that the as-deposited sample of TiAl-based alloys sheet is composed of у, α2 andτ phases with a gradient component change, leading to the spontaneous delamination. The microstructure of as-deposited sheet is of columnar crystals. The columnar crystals and τ phase disappeared, and the a2 phase decreased greatly after vacuum annealing treatment at 1000 ℃ for 16 h, and the component tended to be uniform. After vacuum hot pressing treatment at 1250 ℃ for 1 h, the relative density of samples is increased obviously. Compared with the as-deposited samples, the fractographs of as-annealed or as-pressed samples were intergranular fracture and cleavage fracture. diverted from the intergranular fracture to the mixed manner of intergranular fracture and cleavage fracture.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2007年第6期973-976,共4页
Rare Metal Materials and Engineering
基金
国家自然科学基金(90205034&90405016)资助
关键词
电子束物理气相沉积
TIAL基合金
薄板
物相组成
显微分析
electron beam-physical vapor deposition
TiAl-based alloys
sheet
phase composition
microanalysis