在高温循环负荷下,FGH96超合金的疲劳行为
Zhengguang Li1, Haiqin Qin1, Kejun Xu1
1Qingdao Campus, Naval Aviation University, Qingdao 266041, China.
Materials (Basel, Switzerland)
|September 9, 2023
概括
超级合金FGH96表现出不同的循环反应和增加的拉切特应变,在550°C的保持时间. 高温氧化和保持时间显著改变其机械性能和断裂模式.
科学领域:
- 材料科学 材料科学 材料科学
- 机械工程 机械工程
- 金工业是金工业的一个方面.
背景情况:
- FGH96超级合金对于高温应用至关重要.
- 了解其在联合疲劳和爬行条件下的行为对于结构完整性至关重要.
研究的目的:
- 研究FGH96超合金在550°C的低循环疲劳 (LCF) 和爬行疲劳相互作用 (CFI) 的行为.
- 为了分析循环软化/硬化和拉切特征.
- 为了确定不同负载条件下的故障机制.
主要方法:
- 在550°C进行压力控制的LCF测试.
- 进行压力控制的CFI测试,在峰值压力时保持时间变化.
- 分析断裂表面以了解故障机制.
主要成果:
- FGH96超合金表现出不同的循环软化和硬化行为,取决于应变幅度.
- 在峰值应力时引入持有时间,在不对称周期下显著增加了拉切特应变.
- 断裂分析显示,应变幅度,高温氧化和保持时间影响机械性能和断裂模式.
结论:
- FGH96超级合金的机械反应对应变幅度和持有时间的存在敏感.
- 爬行疲劳的相互作用,特别是保持时间,加剧了材料降解,改变了故障机制.
- 这些发现对于预测使用寿命和确保FGH96超合金制成的组件在高温环境中的安全至关重要.
相关概念视频
Fatigue
204
Fatigue occurs when materials rupture under repeated or fluctuating loads, even at stress levels far below their static breaking strength. It typically results in brittle failure, even for ductile materials. It is a critical consideration in designing machines and structural components subjected to repetitive or varying loads. The nature of these loadings can range from fluctuating loads like unbalanced pump impellers causing vibrations to repeatedly bending a thin steel rod wire back and forth...
204
Fatigue Strength of Concrete
216
Fatigue, in the context of materials science and engineering, refers to the weakening or failure of a material caused by repeatedly applied loads, even if these loads are below the strength limit of the material. Fatigue strength in concrete is a critical property that influences its durability and longevity. Concrete can fail in two ways due to fatigue. Static fatigue or creep rupture occurs under a constant load or one that increases slowly. The other failure mode is due to cyclical or...
216
Stresses under Combined Loadings
171
When analyzing a bent tube with a circular cross-section subjected to multiple forces, it is crucial to determine the stress distribution in order to maintain structural integrity under varied load conditions.
The process begins by slicing the tube at critical points and analyzing the internal forces and stress components at these sections, focusing on the centroid. Normal stresses, generated by axial forces and bending moments, are either compressive or tensile and vary across the section from...
The process begins by slicing the tube at critical points and analyzing the internal forces and stress components at these sections, focusing on the centroid. Normal stresses, generated by axial forces and bending moments, are either compressive or tensile and vary across the section from...
171
Plastic Behavior
219
A material's elastic behavior is characterized by the disappearance of stress once the load is removed, allowing the material to return to its original state. However, when stress surpasses the yield point, yielding commences, marking the onset of plastic deformation or permanent set. This change from elastic to plastic behavior is influenced by the peak stress value and the duration before the load is removed. An intriguing observation occurs when a specimen is loaded, unloaded, and...
219
Stress-Strain Diagram - Ductile Materials
821
The stress-strain relationship in ductile materials such as structural steel or aluminium is intricate and progresses through several stages. When a specimen is loaded, it initially exhibits a linear length increase, depicted by a steep straight line on the stress-strain diagram. It indicates the material is elastically deforming and will return to its original shape once unloaded. However, when a critical stress value is reached, plastic deformation begins. This stage sees substantial...
821
Yield Criteria for Ductile Materials under Plane Stress
185
In designing structural elements and machine parts using ductile materials, it is crucial to ensure that these components withstand applied stresses without yielding. Yielding is initially determined through a tensile test, which evaluates the material's response to uniaxial stress. However, tensile stress is insufficient when components face biaxial or plane stress conditions This condition requires advanced criteria to predict failure.
The Maximum Shearing Stress Criterion, also known as...
The Maximum Shearing Stress Criterion, also known as...
185


