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

作　　者：鲍俊 玄伟东[2] 樊志明 曹后帆 李寒松 王保军[2] 任忠鸣[2] BAO Jun;XUAN Wei-dong;FAN Zhi-ming;CAO Hou-fan;LI Han-song;WANG Bao-jun;REN Zhong-ming(AECC Commercial Aircraft Engine Cooperation Ltd.,Shanghai 200241,China;State Key Laboratory of Advanced Special Steel,Shanghai 200444,China)

机构地区：[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

出　　处：《铸造》2024年第4期476-480,共5页Foundry

基　　金：国家自然科学基金(52274386,92060104);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(No.AR966)。

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0.4~0.5μm,且排列整齐,枝晶间有尺寸为1.5~2.6μm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。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 cuboidalγ′phase on the dendrite branches,measuring 0.4-0.5μm and arranged in an orderly fashion.Petal-shapedγ′phase with sizes ranging from 1.5-2.6μm 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 

分 类 号：TG132.32[一般工业技术—材料科学与工程]