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Baosteel Technical Research 2017年第3期11卷 18-23页

作者： ZHANG Wei ZHOU Deqiang Research Institute Baoshan Iron & Steel Co. Ltd. Shanghai 200431 China

Strain-induced martensitic phase transformation and its influence on the forrnability of newly developed nitrogen-alloyed metastable austenitic stainless steels were systematically investigated. Yield strength for the as- received steels bearing low nickel content was around 300 MPa and their elongation ratios varied from 55.2% to 61.7%. Erichsen numbers of these samples differed from 13.82 to 14.57 mm. Although its Cu content was lower than that of other samples, steel D2 exhibited better plasticity and formability, which was attributed to ~/--,c~＇ martensitic phase transformation. EBSD, XRD, and magnetism tests showed that increases in deformation ratio gradually increased the α＇ martensite phase of a sample ,thereby contributing to its strain and inducing the optimal transformation-induced plasticity effect. An Meeo/5o temperature of around 20 ℃, which is close to the deformation temperature,provided the austenite with adequate stability and gradually transformed it into martensite, thereby endowing lean ASS with better formability.

关键词： nitrogen-alloyed austenitic stainless steel formability martensitic phase transformation stability

Formation of face-centered cubic titanium in laser surface re-melted commercially pure titanium plate

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Journal of Materials Science & Technology 2018年第5期34卷 767-773页

作者： Zhuo Li Xu Cheng Jia Li Huaming Wang national engineering laboratory of additive manufacturing for large metallic components school of materials science and engineeringbeihang university Beijing 100191 China

Micron-scale face-centered cubic titanium phase（named as δ phase） were noticed in the re-melted zone of laser surface re-melted commercially pure titanium *** morphology,sub-structure,orientation and distribution of δ phase were investigated by scanning electron microscopy,electron back-scattered diffraction and transmission electron *** kind formation processes of δ phase were put forward based on the *** first one is α＇→δ transformation which takes place in single α＇grains and leads to the orientation relationship {001}δ//{0001}α＇〈 110 〉 δ//〈 112^-0 〉α＇.The second one is β→α＇＋ δ transformation which takes place at α＇/α＇interfaces and leads to the orientation relationship{001}δ//{11^-0}β〈110〉 δ//〈111〉β.The third one is another kind of β→α＇＋ δ transformation that takes place at α＇/α＇interfaces and leads to the orientation relationship{11^-1}δ//{11^-0}β〈 110 〉 δ//〈 111 〈 β.It is believed that the transformations of δ phase are stress assistant ones and in the present investigation,the phase transformation stress of β→α＇transformation acts as the assistant driving force for the formation of δ phase.

关键词： Pure titanium Laser surface re-melt martensitic phase transformation Face centered cubic Electron back-scattered diffraction

Oxygen addition for improving the strength and plasticity of TiZr-based amorphous alloy composites

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Journal of Materials Science & Technology 2021年第20期79卷 212-221页

作者： Ziyan Zhao Juan Mu Haifeng Zhang Yandong Wang Yang Ren Key Laboratory for Anisotropy and Texture of Materials(MOE) School of Materials Sciences and EngineeringNortheastern UniversityShenyang 110004China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China X-ray Science Division Argonne National LaboratoryArgonneIL 60439USA

The addition of a small amount of oxygen improves the mechanical properties,especially plasticity,of Ti_(45.7)Zr_(33)Ni_(3)Cu_(5.8)Be_(12.5) amorphous alloy composites(AACs)at room temperature(298 K).Compared to the plasticity of AACs without added O(5%),the plasticity of the composites with 0.73 at.%O(nominal composition)was much higher(11%).Even at O content higher than 0.73 at.%,the AACs exhibited good *** highest plasticity of∼12.3%was observed with 2.87 at.%*** distinct mechanisms are proposed to explain the enhanced plasticity of the *** low O content,although deformation-induced phase transformation was suppressed,a substantial amount of α" martensite was *** microstructural features of α" martensite,such as thinner laths and homogeneous distribution,induced the formation of multiple shear bands in the amorphous *** high O content,deformation-induced phase transformation was seriously suppressed.A dispersed nanoωphase was formed during rapid solidification in AACs with O content higher than 1.45 at.%.This resulted in a weakening in the anisotropy ofβdendrites and led to their homogenous ***,multiple shear bands were formed in the amorphous *** from plasticity,the strength of the AACs also increased with an increase in the O *** phenomenon was explained in terms of three mechanisms,*** solid-solution-strengthening effect of O,fine-grain strengthening of β dendrites,and secondary phase strengthening by the nano ω phase.

关键词： Amorphous alloy Composite Oxygen martensitic phase transformation Omega phase

Effect of cold rolling on the microstructural, magnetic, mechanical, and corrosion properties of AISI 316L austenitic stainless steel

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International Journal of Minerals,Metallurgy and Materials 2018年第6期25卷 630-640页

作者： S.Tanhaei Kh.Gheisari S.R.Alavi Zaree Department of Materials Science and Engineering Faculty of Engineering Shahid Chamran University of Ahvaz Steel Research Center Faculty of Engineering Shahid Chamran University of Ahvaz

This study has evaluated the effect of different levels of cold rolling（from 0 to 50%）on the microstructural,magnetic,and mechanical properties and the corrosion behavior of 316L austenitic stainless steel in Na Cl（1 mol/L）＋H_2SO_4（0.5 mol/L）*** examinations using optical microscopy revealed the development of a morphological texture from coaxial to elongated grains during the cold-rolling *** analysis carried out on the basis of X-ray diffraction confirmed the formation of the ferromagneticα′-martensite phase under the stresses applied during cold *** finding is in agreement with magnetic measurements using a vibrating sample *** properties determined by tensile and Vickers microhardness tests demonstrated an upward trend in the hardness-to-yield strength ratio with increasing cold-rolling percentage,representing a reduction in the material’s work-hardening *** and localized corrosion parameters were estimated via potentiodynamic polarization corrosion tests and electrochemical impedance *** contrast to the uniform corrosion,wherein the corrosion current density increased with increasing cold-working degree because of the high density of microstructural defects,the passive potential range and breakdown potential increased by cold working,showing greater resistance to pit *** pits were formed,the cold-rolled material repassivation tendency decreased because of the broader hysteresis anodic loop,as confirmed experimentally by observation of the microscopic features after electrochemical cyclic polarization evaluations.

关键词： 316L stainless steel cold rolling morphological texture martensitic phase transformation work-hardening ability repassivation tendency

martensitic transformation in Cu-doped NiMnGa magnetic shape memory alloys

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Chinese Physics B 2011年第2期20卷 527-531页

作者：李盼盼王敬民蒋成保 Key Laboratory of Aerospace Materials and Performance (Ministry of Education) School of Materials Science and EngineeringBeihang University

This paper studies the martensitic transformation in the Cu-doped NiMnGa alloys. The orthorhombic martensite transforms to L21 cubic austenite by Cu substituting for Ni in the Nis0-xCuxMn31Ga19 （x=2 10） alloys, the martensitic transformation temperature decreases significantly with the rate of 40 K per Cu atom addition. The variation of the Fermi sphere radius （kF） is applied to evaluate the change of the martensitic transformation temperature. The increase of kF leads to the increase of the martensitic transformation temperature.

关键词： shape memory alloys martensitic phase transformation NiCuMnGa

In situ scanning electron microscopy observation of deformation and fracture behavior of Ti-3Zr-2Sn-3Mo-25Nb alloy

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Rare Metals 2012年第4期31卷 318-322页

作者： Ma, Xiqun Yu, Zhentao Han, Yong Song, Xiping Sun, Qiaoyan Northwest Institute for Nonferrous Metal Research Xi'an 710016China State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong UniversityXi'an 710049China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeiiing 100083China

The plastic deformation and fracture processes of Ti-3Zr-2Sn-3Mo-25Nb alloy for surgical implants were directly observed by in situ scanning electron microscopy(SEM).The effect of phase transformations on deformation-induced martensitic transformation accompanying the cyclic tensile fracture processes was *** results reveal that the metastable alpha martensites(α″) promotes deformation-induced martensitic transformation to ductile fracture,whereas the omega(ω) and alpha(α) phases drastically prevent slip dislocation and deformation-induced martensitic transformation to brittle fracture.

关键词： titanium alloys metastable phases martensitic phase transformation deformation

Degeneration and rejuvenation of shape memory effect associated with the precipitation of coherent nano-particles in a Co-Ni-Si shape memory alloy

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Journal of Materials Science & Technology 2021年第17期76卷 150-155页

作者： Huabei Peng Dian Wang Qi Liao Yuhua Wen School of Mechanical Engineering Sichuan UniversityChengdu 610065China

In a solution treated Co-20Ni-6Si shape memory alloy,coherent nano-particles were precipitated after annealing at 873 K for 1 min,but the shape memory effect almost *** is attributed to that the coherent nano-particles not only suppressed the stress-induced face-centered cubic to close-packed hexagonal martensite transformation but also damaged the crystallographic reversibility of reverse martensite *** further annealing at 1073 K for 1 min,the shape memory effect was rejuvenated owing to the dissolution of ***,the recovery strain significantly increased to5.1%from the solution treatment of 3.1%after annealing at 1073 K for 1 min.

关键词： Shape memory alloys martensitic phase transformation Defects Coherent nano-particles

Microstructural evolution in 35CrMnSi steel during multi-cyclic quenching and partitioning heat treatment

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Science China(Technological Sciences) 2013年第10期56卷 2581-2585页

作者： LI Yang XIAO GuiYong CHEN LuBin LU YuPeng Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of Education Shandong University School of Materials Science and Engineering Shandong University

A novel method,***-cyclic quenching and partitioning(M-Q-P)heat treatment,is used to tailor the content of retained austenite(RA)in commercial *** 35CrMnSi steel,5 times of Q-P heat treatment can increase the content of RA from 8vol.%to 17 vol.%.As a result,the ultimate elongation of the steel is improved from 17.4%after the typical Q-P heat treatment to 27.1%after 5 times of Q-P ***,the improved combination of strength and ductility for steels by typical Q-P heat treatment is retained by the multi-cyclic Q-P heat *** is shown that the content of RA in some specific steels,and furthermore their mechanical properties,can be regulated through the M-Q-P.

关键词： steels martensitic phase transformation quenching and partitioning EMPA

Effect of Pd content on crystallization and shape memory properties of Ti-Ni-Pd thin films

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International Journal of Smart and Nano Materials 2011年第1期2卷 9-21页

作者： Hee Young Kim Yimin Yuan Tae-hyun Nam Shuichi Miyazaki Institute of Materials Science University of TsukubaTsukubaIbaraki 305-8573Japan School of Materials Science and Engineering&ERI Gyeongsang National University900 GazwadongJinjuGyeongnam 660-701Korea

The Pd content dependence of the crystallization process of Ti–Ni–(19.1–35.3)Pd(at.%)thin films fabricated by a sputter-deposition method was ***–Ni–(19.1–26.1)Pd(at.%)as-deposited thin films were found to be amorphous,whereas Ti–Ni–(29.1–35.3)Pd(at.%)thin films were crystalline in the as-deposited *** the crystallization temperature and activation energy for the crystallization of the amorphous thin films decrease with increasing Pd *** shape memory effect was confirmed in the in situ crystallized thin *** finer grain size in the in situ crystallized thin film results in a higher critical stress for slip and a smaller recovery strain when compared with the thin film crystallized by post annealing.

关键词： shape memory alloy thin film martensitic phase transformation crystallization sputtering

Influence of recovery heating rate on shape memory effect in up-quenched Cu-Al-Mn alloy

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Transactions of Nonferrous Metals Society of China 2014年第10期24卷 3196-3200页

作者：王珊玲杨琴李小兰彭华备文玉华四川大学分析测试中心成都610065 四川大学制造科学与工程学院成都610064

The effect of recovery heating rate on shape memory effect of the up-quenched Cu-8.88Al-10.27Mn（mass fraction, %） alloy was investigated by optical microscopy, electron transmission microscopy（TEM） and electrical resistivity measurement. It is found that the shape recovery rate decreases as the heating rate decreases. It can reach 75% when the heating rate is 20 ℃/min, while it is only 8% when the heating rate is 1 ℃/min. In situ microstructure observation indicates that the dependence of shape memory effect on recovery heating rate is caused by the stabilization of twinned martensite induced by deformation. The analysis of electrical resistivity shows that the stabilization of twinned martensite may be ascribed to formation of compound defects of vacancies and dislocations at the boundaries of twinned martensite during the slow heating. The compound defects prevent the reverse transformation of twinned martensite.

关键词： Cu-Al-Mn alloy shape memory effect martensitic phase transformation twinning