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α+β钛合金旋转弯曲疲劳性能各向异性研究

稀有金属材料与工程 2024年第2期53卷 435-448页

作者：陈松黄森森马英杰杨杰王倩梁玉雷家峰杨锐沈阳化工大学材料科学与工程学院辽宁沈阳110142 中国科学技术大学材料科学与工程学院辽宁沈阳110016 中国科学院金属研究所师昌绪先进材料创新中心辽宁沈阳110016 南方海洋科学与工程广东省实验室(珠海) 广东珠海519000

研究了微观组织和织构对β锻造的α+β两相钛合金镦饼旋转弯曲疲劳性能各向异性的影响。利用OM、SEM、XRD和EBSD等手段表征了镦饼不同方向及不同厚度处的显微组织以及织构分布,分析了微观组织和织构对旋转弯曲疲劳性能各向异性的影响。... 详细信息

研究了微观组织和织构对β锻造的α+β两相钛合金镦饼旋转弯曲疲劳性能各向异性的影响。利用OM、SEM、XRD和EBSD等手段表征了镦饼不同方向及不同厚度处的显微组织以及织构分布,分析了微观组织和织构对旋转弯曲疲劳性能各向异性的影响。结果表明,合金经β锻造后,呈网篮组织特征,原始β晶粒压扁拉长,且晶界处存在再结晶晶粒;镦饼形成β相//轴向的丝织构和α相//径向的织构。径向试样旋转弯曲疲劳强度优于轴向试样,这与镦饼的原始β晶粒形态和织构类型均有关,原始β晶粒的排布导致不同取向裂纹萌生的难易程度和裂纹扩展路径曲折程度不同;此外,α相和β相织构也造成不同取向在循环加载时滑移系开动难易程度不同造成疲劳强度产生差异。

关键词： α+β钛合金各向异性旋转弯曲疲劳织构

激光选区熔化成形工艺对TA15钛合金内部缺陷与力学性能的影响

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中国有色金属学报 2024年第4期34卷 1227-1239页

作者：雷波朱幼宇姜沐池杨兴远刘意蔡雨升吉海宾雷家峰任德春中国科学院金属研究所师昌绪先进材料创新中心沈阳110016 辽宁大学化学院沈阳110036

利用激光选区熔化(Selective laser melting,SLM)成形技术制备TA15钛合金,通过光学显微镜(Optical microscope,OM)、扫描电镜(Scanning electron microscope,SEM)和室温拉伸等研究了激光功率和扫描速度对SLM成形TA15钛合金内部缺陷与力学性能的影响规律。结果表明:在低激光功率(100~125 W)、高扫描速率(1200~1600 mm/s)区域,激光能量密度较低,合金内部缺陷主要为不规则形状的缺陷;在高激光功率(150~200 W)、低扫描速度(800~1000 mm/s)区域,激光能量密度过高,合金内部缺陷主要为规则球形缺陷。规则球形缺陷的存在会导致合金塑性显著降低、对强度影响较弱;而不规则未熔合缺陷的存在会显著降低合金强度和伸长率。TA15钛合金的最佳工艺参数:激光功率为200 W、激光扫描速度为1600 mm/s时,成形合金拉伸强度为(1291±4.2)MPa,断裂伸长率为(8.5±0.5)%。

关键词：激光选区熔化 TA15钛合金缺陷类型力学性能

航空用TC21钛合金变截面模锻件的显微组织和力学性能不均匀性分析

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金属学报 2024年第3期60卷 333-347页

作者：杨杰黄森森尹慧翟瑞志马英杰向伟罗恒军雷家峰杨锐中国科学技术大学材料科学与工程学院沈阳110016 中国科学院金属研究所师昌绪先进材料创新中心沈阳110016 中国第二重型机械集团德阳万航模锻有限责任公司德阳618000

针对β锻制备的航空用TC21钛合金变截面模锻件的组织和力学性能不均匀性,采用Deform软件模拟、OM、SEM、XRD、EBSD、拉伸和示波冲击,对不同等效应变处的显微组织和力学性能进行表征,对比分析了影响拉伸和冲击及其各向异性的主要因素。... 详细信息

针对β锻制备的航空用TC21钛合金变截面模锻件的组织和力学性能不均匀性,采用Deform软件模拟、OM、SEM、XRD、EBSD、拉伸和示波冲击,对不同等效应变处的显微组织和力学性能进行表征,对比分析了影响拉伸和冲击及其各向异性的主要因素。结果表明,模锻件整体形状复杂,等效应变集中于0.75~1.20范围,应变高处流线组织明显,亚结构增多,窄截面导致冷速较快,使得初生α相含量减少以及次生α相细化,共同导致了强度升高。分析了高应变处在热变形和热处理过程中各相组成的织构演化,最终为残余β相的//LD的强织构及转变α相的{0002}2种较弱织构,从α相滑移系和β相密排面分析了强织构导致的强度各向异性。示波曲线表明冲击功主要消耗于萌生能,结合原始β晶粒排布讨论了不同取向冲击和拉伸断口的断裂模式差异,最后提出拉伸断裂模型,解释了高应变1.20处具有良好强塑性匹配的原因。

关键词： TC21钛合金模锻件等效应变织构力学性能

Effect of Hot Isostatic Pressing Conditions and Cooling Rate on Microstructure and Properties of Ti-6Al-4V Alloy from Atomized Powder

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Journal of Materials Science & Technology 2014年第12期30卷 1289-1295页

作者： lei Xu Ruipeng Guo Chunguang Bai jiafeng lei Rui Yang Institute of Metal Research Chinese Academy of Sciences School of Materials and Metallurgy Northeastern University

The effects of temperature and pressure on density, microstructure and mechanical properties of powder compacts during hot isostatic pressing（HIPping） were investigated. Optimized HIPping parameters of temperature range from 900 to 940℃, pressure over 100 MPa and holding time of 3 h, were obtained. Tensile properties after different heat treatments show that both the geometry of samples and cooling rate have a significant influence on mechanical properties. Finite element method was used to predict the temperature field distribution during HIPped sample cooling, and the experimental results are in agreement with simulation prediction. The interaction of HIPping parameters was analyzed based on the response surface methodology（RSM） in this study.

关键词： Hot isostatic pressing Ti-6Al-4V Cooling rate Microstructure Mechanical properties

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焊前预处理对钛合金厚板焊接残余应力的影响

金属学报 2024年第8期60卷 1064-1078页

作者：周牧王倩王延绪翟梓融何伦华李昺马英杰雷家峰杨锐中国科学技术大学材料科学与工程学院沈阳110016 中国科学院金属研究所师昌绪先进材料创新中心沈阳110016 中国科学院金属研究所沈阳材料科学国家研究中心沈阳110016 上海科技大学智造系统工程中心上海201210 散裂中子源科学中心东莞523803 中国科学院物理研究所北京国家凝聚态物理学实验室北京100190

焊接残余应力是影响焊接成型及焊接部件服役的重要因素。为了优化焊接工艺和焊接接头微观结构,有效地减小焊接残余应力,本工作研究了焊前预处理工艺对电子束焊接钛合金厚板焊接接头组织、性能和残余应力的影响机制。对不同预处理工艺制... 详细信息

焊接残余应力是影响焊接成型及焊接部件服役的重要因素。为了优化焊接工艺和焊接接头微观结构,有效地减小焊接残余应力,本工作研究了焊前预处理工艺对电子束焊接钛合金厚板焊接接头组织、性能和残余应力的影响机制。对不同预处理工艺制备的钛合金焊接接头进行组织形貌表征,发现焊前预热显著增宽了焊接接头的熔合区和热影响区,粗化了两区域内的α片层,提高了焊接接头的强韧性匹配。采用中子衍射法、深孔法和轮廓法检测钛合金厚板电子束焊接头残余应力,对3种方法的检测结果进行对比分析,获得了焊接接头不同区域沿不同方向的残余应力分布。另外,对比了2种预热工艺焊接接头采用深孔法获得的残余应力结果,发现焊前预热可以显著降低焊接接头的残余应力。采用数值模拟计算了不同预热温度下温度场和应力场的变化情况,获得了不同预热温度条件下热应力的动态变化规律,揭示了预热降低残余应力的内在机理。对比2种预处理工艺焊接接头熔合区和热影响区的显微组织、元素分布和晶粒取向,进一步阐明了预热可以通过促进元素扩散和诱发变体选择降低β→α相变产生的应力集中。

关键词：钛合金残余应力中子衍射显微组织力学性能

Influence of Processing Conditions on Microstructure and Mechanical Properties of Large Thin-Wall Centrifugal Ti–6Al–4V Casting

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Journal of Materials Science & Technology 2016年第4期32卷 362-371页

作者： Xin Feng Jianke Qiu Yingjie Ma jiafeng lei Yuyou Cui Xinhua Wu Rui Yang Institute of Metal Research Chinese Academy of Sciences Department of Materials Engineering Monash University

In this work, the effects of mould pre-heating temperatures and hot isostatic pressing （HIPping） process on the microstructural characteristics and mechanical properties, including static tensile and damage- tolerance properties of large thin-wall cylindrical Ti-6Al-4V casting, have been studied. The experimental results show that with the increasing mould pre-heating temperature from 673 to 873 K, the casting mi- crostructures change from a mixture of Widmanstatten and colony microstructure to a primary colony. The centre of the thick wall section has relatively coarse microstructure than the edge and thin section. Lower mould pre-heating temperature brings about more porosities. HIPping process, which not only reduces the casting pores effectively but also increases the prior β grain boundary cohesion and coars- ens the microstructure, is essential to improving the ductility of the casting. Due to the oxygen contamination and finer microstructure on the surface, micro-hardness profiles on the cross section present a decreas- ing tendency from the surface to inner. The thickness of the reaction layers for the different mould pre-heating temperatures is nearly the same （-450 μm）. On the whole, the tensile strength and micro- hardness decrease with increasing mould pre-heating temperature from 673 to 873 K. However, the fracture toughness and fatigue crack growth resistance of the castings increase with increasing mould pre- heating temperature.

关键词： Ti-6Al-4V alloyCentrifugal investment castingHot isostatic pressingCasting microstructureTensile propertiesDamage-tolerance properties

Formation mechanism of α lamellae during β→α transformation in polycrystalline dual-phase Ti alloys

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Journal of Materials Science & Technology 2021年第12期71卷 98-108页

作者： Jia Sun Min Qi Jinhu Zhang Xuexiong Li Hao Wang Yingjie Ma Dongsheng Xu jiafeng lei Rui Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016China University of Shanghai for Science and Technology Shanghai 200093China University of Chinese Academy of Sciences Beijing 100049China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

Phase field simulations incorporating contributions from chemical free energy and anisotropic interfacial energy are presented for theβ→αtransformation in Ti-6 Al-4 V alloy to investigate the growth mechanism ofαlamellae of various morphologies from undercooledβ***αcolony close to realistic microstructure was generated by coupling the Thermo-Calc thermodynamic parameters ofαandβphases with the phase field governing *** simulations show thatαlamellar side branches with feathery morphology can form under a certain combination of interfacial energy anisotropy and temperature.αlamellae tend to grow slowly at high heat treatment temperature and become wider and thicker as temperature increase from 800 to 900℃provided that the interfacial energy anisotropy ratio k_(x):k_(y) was set as 0.1:***,higher interfacial energy anisotropy can accelerate the formation ofαlamellae,and the equilibrium shape ofαlamellae changes from rod to plate as the interface energy anisotropy ratio k_(x):k_(y) vary from 0.1:0.4 to 0.1:0.8 under 820℃.Experiments were conducted to study theαlamellar side branches in Ti-6 Al-4 V(Ti-6.01 Al-3.98 V,wt.%)and Ti-4211(Ti-4.02 A1-2.52 V-1.54 Mo-1.03 Fe,wt.%)alloys with lamellar micro *** backscatter diffraction(EBSD)re sults show thatαlamellar side branches and their related lamellae share the same *** predicted temperature range forαlamellar side branches fo rmation under various interfacial energy anisotropy is consistent with experimental results.

关键词： αLamellae Side branches Ti-6Al-4V Interfacial energy anisotropy Phase field model

激光增材制造高温合金原位增强钛合金复合材料的组织与力学性能

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材料工程 2024年第3期52卷 33-43页

作者：朱幼宇任德春雷波姜沐池杨兴远刘意蔡雨升吉海宾雷家峰中国科学技术大学材料科学与工程学院沈阳110016 中国科学院金属研究所师昌绪先进材料创新中心沈阳110016

采用激光选区熔化成形(selective laser melting,SLM)技术制备TCGH(TC4+GH4169)复合材料,探究TCGH钛合金复合材料的最佳成形工艺参数,并研究沉积态试样和热处理试样的显微组织与力学性能。结果表明:TCGH钛合金复合材料的最佳工艺参数为... 详细信息

采用激光选区熔化成形(selective laser melting,SLM)技术制备TCGH(TC4+GH4169)复合材料,探究TCGH钛合金复合材料的最佳成形工艺参数,并研究沉积态试样和热处理试样的显微组织与力学性能。结果表明:TCGH钛合金复合材料的最佳工艺参数为扫描速率900 mm/s、激光功率150 W,致密度达到99.5%以上。GH4169粉末的添加改变了TC4钛合金材料的固态相变行为,沉积态组织呈现明显高温凝固特征,使得逐行扫描搭接和逐层扫描堆积成形特征变得明显,沿打印方向原始粗大柱状β晶粒尺寸明显减小,复合材料抗拉强度提升。与沉积态试样相比,950℃热处理后,试样显微组织转变为近等轴组织,同时随着热处理温度上升,第二相的回溶导致复合材料的固溶强化作用占主导地位,使得复合材料抗拉强度和塑性均得到提升。

关键词：激光选区熔化 TC4复合材料 GH4169 热处理

Fatigue crack tip plastic zone ofα+βtitanium alloy with Widmanstatten microstructure

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Journal of Materials Science & Technology 2018年第11期34卷 2107-2115页

作者： Yingjie Ma Sabry S.Youssef Xin Feng Hao Wang Sensen Huang Jianke Qiu jiafeng lei Rui Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016China University of Science and Technology of China(USTC) Hefei 230026China Northeastern University Shenyang 110089China

The recent studies had focused on the fatigue crack propagation behaviors of α＋β titanium alloys with Widmanstatten microstructure. The fascinated interest of this type of microstructure is due to the superior fatigue crack propagation resistance and fracture toughness as compared to other microstructures,which was believed to be related to the fatigue crack tip plastic zone（CTPZ）. In this study, the plastic deformation in fatigue CTPZ of Ti-6 A1-4 V titanium alloy with Widmanstatten microstructure was characterized by scanning electron microscope（SEM） and electron backscatter diffraction（EBSD）. The results showed that large-scale slipping and deformation twinning were generated in fatigue CTPZ due to the crystallographic feature of the Widmanstatten microstructure. The activation of twinning was related to the rank of Schmid factor（SF） and the diversity of twin variants developing behaviors reflected the influence of SF rank. The sizes of CTPZ under different stress intensity factors（K） were examined by the white-light coherence method, and the results revealed that the range of the plastic zone is enlarged with the increasing K（or crack length）, while the plastic strain decreased rapidly with the increasing distance from the crack surface. The large-scale slipping and deformation twinning in Widmannstatten microstructure remarkably expanded the range of fatigue CTPZ, which would lead to the obvious larger size of the observed CTPZ than that of the theoretically calculated size.

关键词： Titanium alloy Widmanstatten microstructure CTPZ Slip Deformation twinning