| 摘要: |
| 对TC4进行超声喷丸（USSP）处理得到表面梯度结构，并于350 ℃分别进行60、120、180和240 min热处理。采用光学显微镜（OM）表征其微观组织，X射线衍射仪（XRD）测得残余应力场分布；通过扫描电镜（SEM）、透射电镜（TEM）分别对其疲劳断口形貌、裂纹源组织进行表征。结果表明，超声喷丸处理引入的残余应力场，随热处理时间的延长，残余应力特征参数值（σsrs、σmrs、Zm和Z0）逐渐降低。原始试样疲劳裂纹从表层萌生，超声喷丸试样疲劳裂纹以单一裂纹源形式从次表层萌生，超声喷丸+热处理试样以多源裂纹形式从次表层萌生。 |
| 关键词: 超声喷丸 疲劳极限 残余应力 断口组织形貌 |
| DOI：10.11933/j.issn.1007-9289.20180629002 |
| 分类号:TG668 |
| 基金项目:国家自然科学基金（51274160）；西安市科技计划项目（CXY1438（3）） |
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| Effects of Heat Treatment on Fatigue Property of Ultrasonic Shot Peening TC4 |
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ZHANG Conghui, REN Haitao, RONG Hua, LIU Ying
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College of Metallurgy Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
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| Abstract: |
| Ultrasonic shot peening (USSP) was applied to the TC4 to achieve surface gradient structure.The heat treatment of TC4 was performed at 350℃ for 60, 120, 180, and 240 min. The microstructure was characterized by optical microscopy (OM), and the distribution of residual stress field was measured by X-ray diffractometer (XRD). The fatigue fracture morphology and microstructure of the crack source were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results show that the residual stress field introduces by ultrasonic shot peening treatment decreases gradually with the increase of heat treatment time, and the residual stress characteristic parameters (σsrs, σmrs, Zm and Z0) gradually decrease.The fatigue cracks of the original samples are initiated from the surface layer, and the fatigue cracks of the ultrasonic shot peening specimens are initiated from the subsurface layer in form of a single crack source. The ultrasonic shot peening combining with heat treated specimens are initiated from the subsurface layer in form of multi-source cracks. |
| Key words: ultrasonic shot peening fatigue limit residual stress fracture morphology |
