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transformation behaviors of Ti_(48.5)Ni_(48)Fe_2Nb_(1.5) dependence of annealing and thermomechanical cycling

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Rare Metals 2012年第3期31卷 231-236页

作者： Liu, Ying Liu, Fushun School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Beijing 100191 China

The effect of annealing treatments and thermomechanical cycling on the transformation behaviors and shape memory effect of Ti48.5Ni48Fe2Nb1.5 shape memory alloys were investigated using electrical resistivity measurement and tensile testing. It is found that the transformation behaviors are influenced considerably by the annealing treatments. Both Ms and As increase with increasing annealing temperature and cooling rate. Martensite stabilization occurs during thermomechanical cycles, thus resulting in lower Ms and recovery ratio. Moreover, thermomechanical cycling leads to pseudo-elasticity. The yield point of stress-induced martensite (σSIM) increases with increasing cycles and pre-formation.

关键词： thermomechanical annealing transformation behavior shape memory alloys

transformation behaviors,structural and magnetic characteristics of Ni-Mn-Ga films on MgO(001)

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Chinese Physics B 2013年第10期22卷 522-528页

作者：谢忍唐少龙唐妍梅刘枭辰唐涛都有为 National Laboratory of Microstructures Jiangsu Provincial Laboratory for Nanotechnology and Department of PhysicsNanjing University

Ferromagnetic Ni-Mn-Ga films were fabricated by depositing on MgO （001） substrates at temperatures from 673 K to 923 K. Microstructure, crystal structure, martensitic transformation behavior, and magnetic properties of the films were studied. With increasing deposition temperature, the surface morphology of the films transforms from granular to continu- ous. The martensitic transformation temperature is not dependent on deposition temperature; while transformation behavior is affected substantially by deposition temperature. X-ray analysis reveals that the film deposited at 873 K has a 7M marten- site phase, and its magnetization curve provides a typical step-increase, indicating the occurrence of magnetically induced reorientation （MIR）. In situ magnetic domain structure observation on the film deposited at 873 K reflects that the marten- sitic transformation could be divided into two periods： nucleation and growth, in the form of stripe domains. The MIR occurs at the temperature at which martensitic transformation starts, and the switching field increases with the decrease of temperature due to damped thermal activation. The magnetically induced martensitic transformation is related to the difference of magnetization between martensite and austenite. A shift of martensite temperature of dT/dH = 0.43 K/T is observed, consistent with the theoretical value, 0.41 K/T.

关键词： Ni-Mn-Ga film ferromagnetic-shape memory alloy transformation behavior magnetically in-duced reorientation magnetically induced martensitic transformation

Effects of Composition and Thermal Cycle on transformation behaviors,Thermal Stability and Mechanical Properties of CuAlAg Alloy

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Journal of Materials Science & Technology 2003年第5期19卷 431-434页

作者： Yunqing MA, Chengbao JIANG, Lifen DENG and Huibin XUDepartment of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China Dept. of Mat. Sci. and Eng. Beijing Univ. of Aero. and Astron. Beijing 100083 China

The phase transformation behavior, mechanical properties, and the thermal stability of CuAlAg alloy were studied and minor rare earth (0.1 wt pct La+Ce) was added to improve the mechanical property of the studied alloy. It was found that Ag addition in the CuAl binary alloy can improve the stability of martensitic transformation and high Al content leads to the disappearing of martensitic transformation. The tensile strength and strain of the Cu-10.6AI-5.8Ag (wt pct) alloy were measured to be 383.5 MPa and 0.86%, respectively. With rare earth addition, the tensile strain increased from 0.86% to 1.47%. The CuAlAg alloy did not exhibit martensitic transformation on the second heating process. Its poor thermal stability still needs to be improved.

关键词： High temperature shape memory alloys CuAlAg transformation behavior Thermal cycle Thermal stability Rare earth Mechanical property

Study on the influence of crown ether on arsenic behavior during coal pyrolysis

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Journal of Coal Science & Engineering(China) 2013年第3期19卷 375-380页

作者： Bao-Feng WANG Li-Rong LI Yong-Man ZHU Qiang KANG Jin-Jun ZHANG School of Chemistry and Material Science Shanxi Normal University Linfen 041004 China

The influence of crown ether on behaviors of arsenic at different temperatures and residence time was investigated during the pyrolysis of Tuanbo （TB） coal. The modes of occurrence of arsenic were determined by sequential chemical extraction, density fractionation and demineralization. The results indicated that at the same temperature and residence time, the arsenic removal adding dibenzo-18-crown-6 was higher than that adding 18-crown-6, and were all higher than that of TB coal during pyrolysis. When temperature was 850 ℃ and residence time was 30 min, the arsenic removal of TB coal was 30.63%; at the same condition, the arsenic removal while adding 18-crown-6 was 33.21%, higher than that of TB coal; and the arsenic removal while adding dibenzo-18-crown-6 was 67.41%, significantly higher than that of TB coal. From the results, we can see that adding crown ether can improve the arsenic removal during coal pyrolysis, and especially be conducive to the arsenic which is mainly associated with sulfates ＆ monosulfides and that in stable forms.

关键词： coal pyrolysis crown ether arsenic removal transformation behavior

Laser powder bed fusion additive manufacturing of NiTi shape memory alloys: a review

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International Journal of Extreme Manufacturing 2023年第3期5卷 1-29页

作者： Shuaishuai Wei Jinliang Zhang Lei Zhang Yuanjie Zhang Bo Song Xiaobo Wang Junxiang Fan Qi Liu Yusheng Shi State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074People’s Republic of China Department of Mechanical Engineering City University of Hong KongTat Chee AvenueKowloonHong KongPeople’s Republic of China Science and Technology on Power Beam Processes Laboratory Beijing Key Laboratory of High Power Beam Additive Manufacturing Technology and EquipmentAeronautical Key Laboratory for Additive Manufacturing TechnologiesAVIC Manufacturing Technology InstituteBeijing 100024People’s Republic of China

NiTi alloys have drawn significant attentions in biomedical and aerospace fields due to their unique shape memory effect(SME),superelasticity(SE),damping characteristics,high corrosion resistance,and good *** of the unsatisfying processabilities and manufacturing requirements of complex NiTi components,additive manufacturing technology,especially laser powder bed fusion(LPBF),is appropriate for fabricating NiTi *** paper comprehensively summarizes recent research on the NiTi alloys fabricated by LPBF,including printability,microstructural characteristics,phase transformation behaviors,lattice structures,and *** parameters and microstructural features mainly influence the printability of LPBF-processed NiTi *** phase transformation behaviors between austenite and martensite phases,phase transformation temperatures,and an overview of the influencing factors are summarized in this *** paper provides a comprehensive review of the mechanical properties with unique strain-stress responses,which comprise tensile mechanical properties,thermomechanical properties(*** stress to induce martensitic transformation,thermo-recoverable strain,and SE strain),damping properties and ***,several common structures(e.g.a negative Poisson’s ratio structure and a diamond-like structure)are considered,and the corresponding studies are *** illustrates the various fields of application,including biological scaffolds,shock absorbers,and driving *** the end,the paper concludes with the main achievements from the recent studies and puts forward the limitations and development tendencies in the future.

关键词： NiTi shape memory alloys laser powder bed fusion transformation behavior thermomechanical response lattice structures