生物医用Ti-Nb-(Ta)-Zr合金的微观结构与性能

采用显微硬度测试、X射线衍射分析和透射电子显微镜观察等方法,研究不同热处理后生物医用Ti-35Nb-5Ta-7Zr合金和Ti-35Nb-7Zr合金的显微硬度变化及微观组织特征,揭示Ta元素的添加对合金微观结构、时效析出序列及性能的影响。结果表明:Ti-35Nb-5Ta-7Zr合金比Ti-35Nb-7Zr合金具有更明显的时效强化效果;固溶处理(ST)后经300和600℃时效处理,Ti-35Nb-5Ta-7Zr合金的时效析出顺序可以描述为β+α″(ST)300℃→β+α600℃→β+α+等温ω,而Ti-35Nb-7Zr合金的时效析出顺序为β+α″+淬火ω(ST)300℃→β+α+等温ω600℃→β+α;Ta元素的添加抑制固溶处理过程中淬火ω相的析出,提高时效过程中等温ω相的析出温度。     

Recovery,recrystallization and phase transformations during thermomechanical processing and treatment of TiAl-based alloys

The conversion of the cast microstructure of a Ti–45Al–10Nb (at.%) ingot due to extrusion and subsequent heat treatments was investigated using scanning and transmission electron microscopy. The starting lamellar microstructure was broken down by dynamic recrystallization into a fine-grained duplex microstructure after extrusion, however, a small amount of remnant lamellae was retained. It was found that the fine substructures in the remnant lamellae varied from one area to another. Recrystallization and phase boundary bulging were found to be the major mechanisms responsible for lamellar globularization. The existence of remnant lamellae was ascribed to the anisotropic flow behavior of the starting lamellar colonies. Microstructural and process variables that influence the scale of remnant lamellae will be elucidated. Annealing in the (α+γ) two-phase field cannot eliminate the remnant lamellar structures. However, the detrimental effect of remnant lamellae can be minimized after alpha treatments provided that the remnant lamellae are smaller than about 80 μm.     

Investigation of thermomechanical characteristics of shape-memory alloys of the Ti-Ni-Nb system and of the effect of heat treatment on them

The properties of shape-memory titanium nickelide-based alloys alloyed with niobium have been investigated for use in developing progressive technology for thermomechanical joints of pipelines and cylindrical elements of constructions of couplings fabricated from these alloys. In the process of the investigations, the elemental and phase compositions of alloys of the Ti-Ni-Nb system in the cast and pressed states have been determined; their microstructure, kinetics, and temperatures of phase transformations have been studied; the main mechanical characteristics have been determined; the thermomechanical characteristics and the effect of different types and regimes of heat treatment on them have been investigated. The results of these investigations confirmed the suitability of the alloys for use in thermomechanical joints of pipelines; couplings can be stored at temperatures of up to 40°C without a loss of deformation induced in them. By changing certain mechanical and thermomechanical characteristics of alloys of the Ti-Ni-Nb system in the cast and pressed states using different types and regimes of heat treatment, the field of employment of these materials can be expanded.     

Structure and magnetic properties ofhigh-performanced Sm2（Co, Fe, Cu, Zr）17 alloys

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｈｉｇｈＣｕｒｉｅｔｅｍｐｅｒａｔｕｒｅａｎｄｌｏｗｅｓｔｔｅｍｐｅｒａ ｔｕｒｅｃｏｅｆｆｉｃｉｅｎｔｏｆｔｈｅＳｍ2 Ｃｏ17ｐｅｒｍａｎｅｎｔｍａｇｎｅｔｓｍａｋｅｔｈｅｍｂｅｉｄｅａｌｃａｎｄｉｄａｔｅｓｆｏｒｈｉｇｈｔ     

Martensitic transformation,shape memory effect and superelasticity of Ti-xZr-(30-x)Nb-4Ta alloys

Martensitic transformations,mechanical properties,shape memory effect and superelasticity of Ti-xZr-(30-x)Nb-4Ta(x=15,16,17 and 18;at%) alloys were investigated.X-ray diffraction(XRD),optical microscopy(OM) and transmission electron microscopy(TEM) results indicated that the Ti-16Zr-14Nb-4Ta,Ti-17Zr-13Nb-4Ta and Ti-18Zr-12Nb4Ta alloys were mainly composed of α″-martensite,while the Ti-15Zr-15Nb-4Ta alloy was characterized by predominant p phase.The reverse martensitic transformation temperatures increased when Nb was replaced by Zr,indicating stronger p-stabilizing effect for the former.The Ti-15Zr-15Nb-4Ta alloy displayed superelasticity during tensile deformation with a recovery strain of 3.51%.For the other three alloys with higher Zr content,the martensitic reorientation occurred during tensile deformation,resulting in shape memory recovery upon subsequent heating.The maximum shape memory effect was 3.46% in the Ti-18Zr-12Nb-4Ta alloy.     

CuZn(Cr，Zr)合金的热变形行为

制备了ＣｕＺｎ和ＣｕＺｎＣｒＺｒ两种合金，用Ｇｌｅｅｂｌｅ－１５００测定它们在恒温和恒速下的稳态变形抗力绘制成ｌｎσ－１／Ｔ关系曲线，从而确定合金的变形激话能Ｑ和应力指数ｎ，并观察了热变形组织。结果表明；在Ｃｕ１３Ｚｎ合金中加入０．１％Ｚｒ和０．１％Ｃｒ，对合金的动态再结晶有强烈抑制作用，合金在６５０～８２０℃之间热变表为不完全动态再结晶组织，而Ｃｕ１３Ｚｎ合金在７５０～８２０℃之间为完全动态再结     

Microstructure and shape-memory characteristics of Ni56Mn25−xCoxGa19 (x = 4, 8) high-temperature shape-memory alloys

NiMnCoGa alloys were studied as candidate of high-temperature shape-memory alloys with Mn substituted by Co. The results show that the hot workability and room-temperature ductility of NiMnGa alloys can be greatly improved by forming ductile γ phase through Co addition. When the amount of γ phase is about 19%, the tensile stress and strain are 491 MPa and 8.2%, respectively. When the amount of γ phase increased to about 43%, the tensile stress and strain are 729.3 MPa and 14.1%, respectively. The reversible strain due to shape-memory effect is 2.1% under a prestrain of 5.3% for x = 4, and the shape-memory ability almost disappears for x = 8 due to large amount of γ phase, which seriously hampers the reorientation of martensitic variants and/or detwinning.     

Mg-Gd-Y-(Mn, Zr)合金的显微组织和力学性能

采用溶剂保护方法制备了合金Mg-9Gd-4Y-0.65Mn和Mg-9Gd-4Y-0.6Zr,并挤压成棒材。通过光学显微镜、X射线衍射仪、扫描电镜和透射电镜等分析研究了这两种合金铸态和变形态的显微组织和力学性能。结果表明:铸态含Mn合金的晶粒粗大,而含Zr合金的晶粒细得多,Zr能有效地细化Mg-RE合金的晶粒;热变形加工使两种合金的晶粒度大大减小,拉伸强度大幅提高,在同等加工条件下,含Mn合金形变细化晶粒作用更显著;两种变形合金都有非常高的室温和300℃高温强度,但含Mn合金的延伸率较高;含Zr变形镁合金适宜通过T5处理,而含Mn变形镁合金适宜通过T6处理提高其综合拉伸力学性能。     

Structure and magnetic properties of nanocrystalline FeCuNbSiB alloys after a thermomechanical treatment

The peculiarities of the formation of a nanocrystalline structure and induced magnetic anisotropy have been studied in Fe_87?x Cu₁Nb₃Si_xB₉ alloys (x = 0, 4, 6, 8, 9.5, 11, 13.5 at. %) after thermomechanical treatment. Differences in the dynamics of the process of phase separation in the initial amorphous state, final phase composition, and magnitude and sign of induced magnetic anisotropy have been revealed depending on the initial content of silicon.     

Improvement of the shape-memory effect properties of copper alloys by optimization of the heat-treatment regimen

Kiev Polytechnic Institute. Leningrad Shipbuilding Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 35–38, November, 1991.     

钽及钽钨合金冷轧变形过程中的组织和性能

通过显微硬度分析、X射线衍射分析和TEM详细研究了钽及钽钨合金在冷轧变形过程中的组织和性能演变规律,结果表明:W在Ta中具有晶粒细化和强化作用,Ta、Ta-2.5%W和Ta-7.5%W合金在1400℃温度退火1 h后的再结晶晶粒的平均尺寸为45、20和15μm;在冷轧过程中,随着变形量的增加,钽和钽钨合金的显微硬度都逐步提高,当变形量达到99%时,Ta、Ta-2.5%W和Ta-7.5%W的显微硬度分别达到了243、309和359 HV;在Ta中添加W后,合金的位错密度会得到极大的提高,其中Ta-7.5%W合金的位错密度比Ta的高一个数量级;钽和钽钨合金各取向的晶粒中的位错密度不同,其中{200}、{211}、{222}和{110}取向的位错密度依次增大,这与Taylor因子计算的结果一致;TEM研究表明,{100}取向的晶粒中形成了位错胞结构,而{110}取向的晶粒中形成了形变带组织。     

Synergistic effect between Laves phase and Zr Ni phases in Zr(MnVNi)_2 hydrogen storage alloys

１　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＡＢ２ｔｙｐｅＺｒｂａｓｅｄＬａｖｅｓｐｈａｓｅｈｙｄｒｏｇｅｎｓｔｏｒａｇｅａｌｌｏｙｓｈａｖｅｂｅｅｎｓｔｕｄｉｅｄｅｘｔｅｎｓｉｖｅｌｙｄｕｅｔｏｔｈｅｉｒｈｉｇｈｃａｐａｃｉｔｙ，ｌｏｎｇｃｙｃｌｅｌｉｆｅｔｉｍｅａｎｄｔｈｅｐｏｔｅｎｔｉａｌｔｏｂｅｃｏｍｅａｐｒｏｍｉｓｉｎｇｃａｎｄｉｄａｔｅｆｏｒＡＢ５ｔｙｐｅａｌｌｏｙｓｉｎＮｉＭＨｂａｔｔｅｒｉｅｓ［１，２］．ＵｎｌｉｋｅｔｈｅｃｏｍｍｏｎＡＢ５ｔｙｐｅｈｙｄｒｏｇｅｎｓｔｏｒａｇ…     

Through-process simulation of texture and properties during the thermomechanical processing of aluminium sheets

Computer-based alloy and process development requires the integration of models for simulating the evolution of microstructure, microchemistry and crystallographic texture into process models of the thermomechanical production of Al sheet. In this paper, a softening model simulating the progress of recovery and recrystallization and the following texture changes is linked to deformation and microchemistry models. The possibility of such coupled simulations is illustrated by way of the thermomechanical processing of Al–Mn–Mg AA 3104 can stock. In particular, the impact of inter-stand recrystallization between the tandem hot rolling passes as well as recrystallization during coil cooling (“self-annealing”) on the resulting hot strip and final gauge textures are explored. Finally, the predicted textures are input into a polycrystal–plasticity model to simulate anisotropic properties (earing behaviour) of the sheets. Thus, it is possible to link the materials properties at final gauge to the decisive steps of deformation and recrystallization along the thermomechanical process chain.     

Evaluation of glass forming ability in ternary Ni62(Nb,Ta)38 alloys

The parameter γ¹ we previously defined has been proved to be valid in predicting the better glass former in several binary alloy systems, but is hard to be applied in the multi-component alloys because the phase diagrams of these alloys are usually not well constructed. In the present work, we attempt to extend the application of parameter γ¹ to a ternary alloy system and predict the better glass former in the Ni₆₂Nb_38-xTa_x (x = 5, 10, 15, 20, 25, 30, 35) alloys based on the systematic investigation on the phase evolution from Ni₆₂Nb₃₈ to Ni₆₂Ta₃₈. The prediction has been confirmed by the experimental results, indicating the validity of the parameter γ¹ in the Ni₆₂(Nb, Ta)₃₈ ternary alloys.     

Structure of quenched Zr-Pd alloys and the formation of the ω phase in zirconium alloys

Methods of X-ray diffraction, optical metallography, transmission electron microscopy, and measurements of hardness and microhardness have been used to study the structure of quenched alloys of the zirconium-palladium system with a palladium concentration from 1 to 10 at %. It has been established that at the palladium content below 4 at % in the process of quenching in these alloys a eutectoid decomposition occurs and a two-phase structure is formed, which consists of laths of the α phase and particles of an intermetallic compound Zr₂Pd arranged predominantly at the boundaries of laths of the α phase. In the alloys with a palladium content from 5 to 8 at %, there is formed a metastable ω phase. In the alloys with a palladium concentration of 9 and 10 at %, a metastable β phase is revealed. A method of determining the concentration of the alloying component in the ω phase is proposed. It is shown that in the quenched state this concentration is less than the content of the alloying component in the alloy. The behavior of the concentration boundary corresponding to the formation of the ω phase in binary zirconium alloys has been determined depending on the type of the alloying metal.     

合金元素Nb、Ta、Fe、Zr对钛合金组织和性能的影响

综述了Nb、Ta、Fe、Zr四种元素对β钛合金组织和力学性能的影响,以期对合金的设计起到指导作用.