磨削深度对γ-TiAl合金表面完整性和疲劳性能的影响  

Influence of Grinding Depth on the Surface Integrity and Fatigue Property ofγ-TiAl Alloy

作　　者：倪明杰 刘仁慈[1,2] 周浩浩 杨超 葛术宇 刘冬 史凤岭[3] 崔玉友 杨锐 NI Mingjie;LIU Renci;ZHOU Haohao;YANG Chao;GE Shuyu;LIU Dong;SHI Fengling;CUI Yuyou;YANG Rui(Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China;AECC Shenyang Liming Aero-Engine Co.Ltd.,Shenyang 110043,China;AECC Commercial Aero-Engine Co.Ltd.,Shanghai 200241,China)

机构地区：[1]中国科学院金属研究所师昌绪先进材料创新中心,沈阳110016 [2]中国科学技术大学材料科学与工程学院,沈阳110016 [3]中国航发沈阳黎明航空发动机有限责任公司,沈阳110043 [4]中国航发商用航空发动机有限责任公司,上海200241

出　　处：《金属学报》2024年第2期261-272,共12页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.51701209;中国科学院稳定支持基础研究领域青年团队计划项目No.YSBR-025;云南省重大科技专项计划项目No.202302AB080009。

摘　　要：γ-TiAl合金部件需要磨削加工以保证其装配精度,而低塑性金属间化合物γ-TiAl合金的力学性能对磨削表面完整性极为敏感。本工作研究了磨削深度对γ-TiAl合金样品表面形貌、表层显微组织、显微硬度等表面完整性参数及最终疲劳性能的影响。结果表明,0.5 mm及以上深度磨削样品表面易产生裂纹,而0.2 mm及以下深度磨削样品表面完好,这与磨削变形热温升导致的冷却收缩拉应力过大有关。随着磨削深度增大,粗糙度参数的轮廓算术平均偏差(R_(a))和微观不平度的十点平均高度(R_(z))增大,偏度(R_(sk))减小。表层γ+α_(2)片层沿磨削方向弯曲变形,相应变形层厚度随着磨削量增大而增大,而显微硬度由表及里先减小后增大。γ-TiAl合金650℃加载440 MPa旋转弯曲疲劳寿命随着磨削深度增大而减小,磨削深度0.05 mm的样品疲劳寿命大于106cyc,磨削深度0.2 mm的样品疲劳寿命约为104cyc,其断口裂纹源可观察到磨削痕迹,这与其表面沟槽应力集中有关。γ-TiAl合金疲劳寿命随着R_(z)的增大而减小,2者呈非线性关系;当R_(z)小于4μm时,疲劳寿命稳定在106cyc以上。γ-TiAl is a family of promising structural materials with low density,high stiffness,and good oxidation and creep resistances at elevated temperatures.They can replace heavier nickel-based alloys at 600-800℃;thus,they are used in the construction of low-pressure turbine blades for aeroengines,i.e.,General Electric next-generation and leading edge aviation propulsion.Grinding is an important processing step in blade production to ensure the accuracy of assembling.However,the limited ductility and fracture toughness at room temperature and low thermal conductivity ofγ-TiAl alloys narrow the parameter windows of the grinding process.Cracks often form on the surface when the processing parameters are not well controlled.Additionally,grinding greatly influences the surface integrity(i.e.,roughness,microstructure,and hardness),which influences the mechanical properties,especially those of brittleγ-TiAl alloys that are sensitive to notch.Grinding depth is a major parameter in blade production because it influences quality and efficiency.Investigating the effect of grinding depth on the surface integrity and fatigue properties ofγ-TiAl samples is necessary to optimize the grinding process and identify the major factors of surface integrity that guarantee optimal mechanical properties.In this work,castγ-TiAl alloy(Ti-45Al-2Nb-2Mn-1B,atomic fraction,%)samples were ground with different depths.The surface integrity(surface roughness,microstructure,and microhardness)and fatigue properties of the samples were compared.Cracks were detected in samples ground to 0.5 and 1 mm depths,while no cracks were detected in samples ground to 0.2 mm or less depths,this is related to the tensile stress induced by temperature increase caused by deformation heat.With the increased grinding depth,the number and depth of grooves increased and for the surface roughness parameters,arithmetic mean deviation and 10-point mean roughness(R_(z))increased,while skewness decreased.Theγ+α_(2)lamellae bended in the surface layer and layer thickne

关 键 词：Γ-TIAL 磨削 表面完整性 粗糙度 显微组织 疲劳性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]