检索结果-南通市图书馆

喷丸对TNM-TiAl合金组织以及450℃下高周疲劳性能的影响

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

精密成形工程 2024年第7期16卷 133-143页

作者：葛庚午宿仁杰梁永锋林均品北京科技大学新金属材料国家重点实验室北京100083

目的针对TNM-TiAl合金(Ti-43.5Al-4Nb-1Mo-0.1B)服役时受高周疲劳影响的问题,揭示喷丸处理技术对TNM-TiAl合金疲劳性能的影响规律。方法通过扫描电镜和透射电镜分析喷丸前后的组织演变,测量喷丸前后合金表面残余应力、表面粗糙度和显微... 详细信息

目的针对TNM-TiAl合金(Ti-43.5Al-4Nb-1Mo-0.1B)服役时受高周疲劳影响的问题,揭示喷丸处理技术对TNM-TiAl合金疲劳性能的影响规律。方法通过扫描电镜和透射电镜分析喷丸前后的组织演变,测量喷丸前后合金表面残余应力、表面粗糙度和显微硬度分布规律,采用梯度法测量喷丸前后的高周疲劳极限,并分析断口形貌和断口附近组织。结果喷丸后合金表面粗糙并且存在烧蚀坑,表面附近的片层团发生弯曲,在组织内部引入大量位错、位错缠结以及位错胞等缺陷。喷丸后表面粗糙度明显提高,显微硬度提高了209HV0.05,从表面到内部形成深度为260μm的硬度梯度。喷丸后试样表面的残余压应力为446 MPa,深度约为85μm。喷丸后在450℃下保温30 h后合金表面最大硬度仍比喷丸前的硬度高166HV0.05,硬化深度约为150μm。未喷丸光滑试样、喷丸光滑试样、未喷丸缺口试样和喷丸缺口试样的疲劳极限分别为615、637、385、455 MPa,光滑试样断裂类型为穿晶解理型脆性断裂,而缺口试样为穿晶脆性断裂。结论喷丸能够显著提高最大残余压应力和引入应力的深度,且喷丸引入的组织具有一定的热稳定性,喷丸明显提高了TNM-TiAl合金的疲劳极限。

关键词：喷丸 TNM合金显微组织残余应力高周疲劳性能

Deformation and phase transformation behaviors of a high Nb-containing TiAl alloy compressed at intermediate temperatures

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第7期102卷 89-96页

作者： Xu Liu lin Song Andreas Stark Uwe Lorenz Zhanbing He junpin lin Florian Pyczak Tiebang Zhang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Institute of Materials Research Helmholtz-Zentrum GeesthachtMax Planck-Str.1Geesthacht 21502Germany State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

In modernβ-solidified TiAl alloys,the decomposition of α_(2) phase is frequently observed during heat treatment or high-temperature deformation of the *** this study,high-temperature deformation and decomposition mechanisms of α_(2) phase in a Ti-45Al-8.5Nb-0.2B-0.2W-0.02Y alloy are *** a sample deformed at 800℃,the precipitation ofβ_(o)(ω_(o))phase is observed within the equiaxed α_(2) *** nucleation ofω_(o) particles within theβ_(o) matrix indicates the α_(2)→β_(o)→ω_(o) *** addition,numerous y phase precipitates form within theβ_(o)(ω)*** α_(2) lamellae decompose into ultrafine( α_(2)+γ)lamellae and coarsened y lamellae via α_(2)→ α_(2)+γand α_(2)→γtransformation,***,theω_(o) phase nucleates within the ultrafine lamellae via α_(2)→ω_(o) ***,in a sample deformed at 1000℃,the nucleation ofβ_(o) particles is sluggish,which is caused by the efficient release of the internal stress via dynamic recrystallization(DRX).These results indicate that complex phase transformations can be introduced by the decomposition of α_(2) phase in TiAl alloys with a high amount ofβ-stabilizing elements.

关键词： TiAl alloys Phase transformation Microstructure Electron microscopy

Effects of heat treatments on microstructures of TiAl alloys

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2022年第6期29卷 1225-1230页

作者： Wen Yu Jianxin Zhou Yajun Yin Zhixin Tu Xin Feng Hai Nan junpin lin Xianfei Ding State Key Laboratory of Materials Processing and Die and Mould Technology Huazhong University of Science and TechnologyWuhan 430074China Cast Titanium Alloy R&D Center Beijing Institute of Aeronautical MaterialsBeijing 100095China Beijing Engineering Research Center of Advanced Titanium Alloy Precision Forming Technology Beijing 100095China Beijing Institute of Aeronautical Materials Co. Ltd.Beijing 100094China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

This study aims to investigate the effects of heat treatments on the microstructure ofγ-TiAl *** Ti-47Al-2Cr-2Nb alloy ingots were manufactured by casting method and then heat-treated in two types of heat *** microstructures were studied by both optical and scanning electron *** chemical compositions of two ingots were determined as *** ingot with lower Al content only obtains lamellar structures while the one higher in Al content obtains nearly lamellar and duplex structures after heat treatment within1270 to 1185℃.A small amount of B2 phase is found to be precipitated in both as-cast and heat-treated *** are distributed at grain boundaries when holding at a higher temperature,such as 1260℃.However,B2 phase is precipitated at grain boundaries and in colony interiors simultaneously after heat treatments happened at 1185℃.Furthermore,the effects of heat treatments on grain refinement and other microstructural parameters are discussed.

关键词： TiAl alloys microstructure heat treatment casting

Directional solidification of Ti-45Al-8Nb-(W,B,Y) alloy

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2010年第3期29卷 292-297页

作者： DING Xianfei lin junpin HE Jianping YE Feng CHEN Guoliang State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

Using a Bridgman vertical vacuum furnace,Ti-45Al-8Nb-（W,B,Y）（at.%） bars,which were prepared from a plasma arc melting （PAM） ingot,were directionally solidified at growth rates of 10,15,and 20 μm/*** twinned （PST） crystal with an aligned lamellar microstructure was obtained at the growth rate of 15 μm/s because of high Nb *** principle of PST crystal growth and the effect of Nb element were *** results of investigations on microstructure and micromechanical properties of the directionally solidified （DS） bars of Ti-45Al-8Nb-（W,B,Y） alloy are briefly summarized.

关键词： directional solidification TiA1 alloys larnellar microstructure crystal growth

Improvement in the liquid zinc corrosion resistance of high Nb-TiAl alloys by pre-oxidation in a SiO_2-powder pack

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2012年第2期55卷 505-509页

作者： SUN PengFei ZHANG LaiQi ZHANG Li lin junpin State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

The influence of pre-oxidation on the liquid zinc corrosion resistance of high Nb-TiAl alloys was *** pre-oxidation was performed by heating the specimens,buried in silica powder and encapsulated in a silica tube under a vacuum of 1.3×10-3 Pa at 950°C for 12 *** results showed that the preoxidized sample exhibited much higher liquid zinc corrosion resistance than that for the comparative *** excellent liquid zinc corrosion resistance was attributed to the formation of high-quality oxide scale during *** corrosion of all the samples in liquid zinc was caused by a localized breakdown in the oxide *** continuous and dense oxide scale formed during preoxidation substantially may prevent the liquid zinc from diffusing to the substrate,and its good continuity may also reduce the possibility of localized breakdown in the oxide scale.

关键词：二氧化硅粉末耐腐蚀性预氧化 TIAI合金锌液 TiAl合金氧化铁皮氧化过程

Surface modification of Ti-45Al-8.5 Nb alloys by microarc oxidation to improve high-temperature oxidation resistance

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2018年第3期28卷 386-390页

作者： Fang Cheng Shasha Li Wanyuan Gui junpin lin State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing

Microarc oxidation（MAO）electrolysis plasma deposition was used to prepare Al2O3coatings on Ti-45Al-8.5 Nb alloys to improve high temperature oxidation *** surface and cross-section morphologies before and after high-temperature oxidation,the chemical composition,and the phase identification of the coatings were investigated by scanning electron microscopy（SEM）,electron probe microanalyses（EPMA）,and X-ray diffraction（XRD）.The results show that Al2O3coatings with a thickness of approximately 8μm can be obtained on the Ti-45Al-8.5 Nb alloys by MAO for 600 *** samples with the Al2O3coatings exhibited better high-temperature oxidation resistance.A minimal weight gain of only 0.396 g/m2after 100 h oxidation at 900°C was observed for the coatings formed with a deposition voltage of 400 V and using a duty cycle of 3%.The deposition mechanism of the Al2O3coatings and the effect of the MAO parameters are also described.

关键词： Cathode electrolytic plasma Microarc oxidation High temperature oxidation resistance High Nb-Ti Al alloys Coating

Role of yttrium in glass formation of Ti-based bulk metallic glasses

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2009年第1期28卷 68-71页

作者： HAO Guojian REN Fei ZHANG Yong lin junpin State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

Starting with Zr of two different purities, Ti-based bulk metallic glasses （BMGs） with a nominal composition of Ti40Zr25Cu12Ni3Be20 were prepared. The effect of the addition of yttrium at levels of 0.2 at.%, 0.4 at.%, 0.5 at.%, 0.6 at.%, and 1 at.% on the glass forming ability （GFA） of the alloy has been investigated by means of metallography, X-ray diffraction, and differential scanning calorimetry. Experimental data in-dicates that high impurity content dramatically reduces the glass forming ability. Microalloying with 0.5 at.% Y is effective in suppressing the crystalline phase formation and alleviating the detrimental effect of oxygen in the low-purity alloy. On the contrary, in the alloy contain-ing high-purity element, the effective yttrium addition is less than 0.4 at.%. The results indicate that the beneficial effect of the optimum dopants is mainly due to scavenging the oxygen impurity via the formation of innocuous phase.

关键词： bulk metallic glass titanium microalloying rare metal glass forming ability

Densification behavior of high Nb containing TiAl alloys through reactive hot pressing

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2007年第3期14卷 251-255页

作者： Yanhang Wang junpin lin Yuehui He Yanli Wang Guoliang Chen State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China State Key Laboratory for Powder Metallurgy Central South University Changsha 410083 China

Densification behavior of high Nb containing TiAl alloys through reactive hot pressing was investigated. The results showed that the density of the sample hot pressed at 1400°C could reach a near full density of 98.37%. However, the densification abnormality was observed at 1500°C. The diffusion of elemental Nb during microstructural evolution is an important aspect affecting densification, which will form pore nests. With the increase of hot pressing temperature, the diffusion of Nb becomes more adequate. HIP （Hot isostatic pressing） treatment can only decrease porosity to some extent, but cannot eliminate it completely.

关键词： TiAl based alloy powder metallurgy densification hot pressing

ωo phase precipitation in annealed high Nb containing TiAl alloys

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2015年第2期25卷 147-152页

作者： lin Song Cong Peng Xiangjun Xu Li You Yanli Wang junpin lin State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Materials and Chemistry School Zhongyuan University of Technology

The ordered ω phases in high Nb containing Ti Al(Nb-Ti Al) alloys have been garnering increasing attention in the recent years. However, the investigations on the Nb dependence on the ωoprecipitation are scarce. In this study, the effect of Nb content on the ωoprecipitation in high Nb(6–10 at%) containing Ti Al alloys after long-time annealing at 850 1C has been studied. The results show that small ordered ω particles in the retained βophase cannot be discerned under scanning electron microscope(SEM) but can be observed using transmission electron microscopy(TEM). Although the Nb segregation can be eliminated after the homogenization heat treatment, the ωophase precipitated in all the alloys studied after annealing at 850 1C. TEM examination reveals that the orientation relationship between the ωoand α2phases can be derived as: [0001]ωo//[1120]α2;(1120)ωo//(0001)α2, which indicates that the ωophase is directly transformed from the parent α2phase. Small γ particles are also observed within the ωoareas. The α2-ωot γ decomposition process is expected during annealing. It is concluded that ωophase is an equilibrium phase in high Nb-Ti Al alloys at 850 1C.

关键词： Ti Al alloys Phase transformation Ordered omega phase TEM Annealing