铸造镍基高温合金K417G中高温拉伸断裂机理研究
Study on Tensile Fracture Mechanism of Cast Nickel-Based Superalloy K417G at Medium-High Temperature
鲍俊 1玄伟东 2樊志明 2曹后帆 2李寒松 1王保军 2任忠鸣2
作者信息
- 1. 中国航发商用航空发动机有限责任公司,上海 200241
- 2. 上海大学省部共建高品质特殊钢冶金与制备国家重点实验室,上海 200444
- 折叠
摘要
研究了高温合金K417G热等静压热处理后700℃和950℃时拉伸的断裂机制,使用万能试验机进行中高温拉伸试验,通过扫描电子显微镜对组织、断口形貌、断口纵截面进行观察.结果表明:热处理后试样枝晶形貌明显,枝晶干上γ'相立方度较高,尺寸为0.4～0.5 μm,且排列整齐,枝晶间有尺寸为1.5～2.6 μm的花瓣形γ'相析出.与700℃时试样的拉伸性能相比,950℃时抗拉强度降低了46.3%,而伸长率提高了200%,这说明高温拉伸强度降低,塑性增加.中温拉伸时,枝晶间长条形碳化物是断裂的主要裂纹源及扩展通道.而高温拉伸时,晶界处的碳化物、共晶成为裂纹源,裂纹沿晶界扩展,形成了沿晶断裂形貌.
Abstract
The fracture mechanism of the K417G high-temperature alloy under tensile conditions at 700℃and 950℃after hot isostatic pressing heat treatment was studied.Tensile tests at elevated temperatures were conducted using a universal testing machine,and observations of microstructures,fracture surfaces,and longitudinal sections were carried out through scanning electron microscopy.The results reveal that the dendritic morphology of the samples after heat treatment is pronounced,with a high degree of cuboidal γ'phase on the dendrite branches,measuring 0.4-0.5 μm and arranged in an orderly fashion.Petal-shaped γ'phase with sizes ranging from 1.5-2.6 μm precipitates between the dendrites.Comparing the tensile properties of samples at 950℃to those at 700℃,the tensile strength decreases by 46.3%,while the elongation increases by 200%.This indicates a reduction in high-temperature tensile strength and an increase in plasticity.During moderate-temperature tensile testing,elongated carbides between the dendrites serve as the primary crack initiation and propagation paths.In contrast,during high-temperature tensile testing,carbides at grain boundaries and eutectic constituents act as crack initiation sources,with cracks propagating along grain boundaries,forming a transgranular fracture morphology.
关键词
高温合金/K417G/热等静压热处理/高温拉伸/断裂机理Key words
superalloy/K417G/hot isostatic pressing heat treatment/high-temperature tensile/fracture mechanism引用本文复制引用
基金项目
国家自然科学基金(52274386)
国家自然科学基金(92060104)
上海市经信委工业强基项目(GYQJ-2022-2-02)
航空科学基金重点项目(2022Z0470S6001)
上海市商用飞机发动机联合创新项目(AR966)
出版年
2024
国家科技期刊平台
NSTL
万方数据