超级合金研发现状

评介了超级合金，如钛基合金(钛钼铪合金、钛钼铪铌合金)、镍基合金(镍钼铁合金)、铁基合金(铁钼合金)和钼基合金(钼铼氧化镧、钼铼氧化铈、钼铼氧化钍)等超级合金的研发现状。     

不同铼含量对钼铼合金性能影响研究概述

钼铼合金因其独特的“铼效应”能够显著改善纯钼的低温脆性,进而使其具有优异的低温加工性能、高温力学性能以及抗辐照性能等。本文总结了铼含量对钼铼合金性能的影响,包括钼铼合金的物理性能、加工性能、力学性能、抗辐照性能、腐蚀性能以及焊接性能;对钼铼合金的研究进行了展望,为未来工艺优化及核电系统的设计选材提供参考。     

钼铼合金的结构和性能

总结了钼铼合金研究的最新进展。典型的钼铼合金成份主要有M041Re，M044.5Re和M047．5Re。钼铼合金坯锭的制备一般采用粉末冶金和真空熔炼的方法。当铼含量低于29％时，铼在钼中固溶形成体心立方结构的α相，钼的晶格常数降低。当铼含量高于29％时，形成x相和σ相。钼铼合金合金的熔点、热性能、电性能介于纯钼和纯铼之间，铼可以提高钼的再结晶温度，降低其塑脆转变温度。铼既可以提高钼的强度，也可以大大改善其塑性。钼铼合金的加工硬化率介于纯钼和纯铼之间而靠近纯钼。     

钼铼合金带材的组织和性能

选用熔炼的钼铼合金经过锻造、热拉、冷拉和轧制的方法制备钼铼合金带材，其规格为0．3mm宽0．03mm厚，对其组织和性能进行了研究。结果表明：加工态的拉断力是再结晶状态的2．5倍左右，为24．8N；而延伸率只是再结晶状态的1，3，为3．1％；随着退火温度的提高，钼铼合金的的拉断力直线降低，但延伸率在1723K，30min退火后却最高，金相结果表明1723K退火的钼铼合金带材发生了明显的再结晶。钼铼合金加工态拉伸时其断口表现为准解理断裂，退火后断口表现为明显的韧窝状。铼元素加入钼中，可以提高晶粒和晶粒之间的结合力，使得钼铼合金在拉伸下有很好的延伸率。同时钼铼合金在室温变形时，也容易发生孪晶变形，这一点不同于通常的钼合金。     

钼—铼合金的制造及应用

对钼－铼合金的种类、性质、生产技术及应用情况等作了介绍，这对研究铼在钼合金中的作用、机理及开发生产钼－铼合金材料均具一定的参考价值。     

铼的生产与应用研究进展

铼是难熔金属，主要赋存于斑岩铜钼矿床的辉钼矿和黄铜矿中，铼含量在20～2000g／t之间。从钼精矿焙烧产出的烟尘和淋洗液中回收铼及从钼精矿氧压氧化浸出液中回收铼多采用溶剂萃取法和离子交换法。铼用作制取各种催化剂，如汽油重整、烯烃复分解等。铼也用于生产钼铼合金、钨铼合金、镍基超合金和铌铼合金等。铼的某些配合物用作抗癌药物。     

钼─铼合金的制造及应用

对钼铼合金的种类、性质、生产技术及应用情况等作了介绍，这对研究铼在钼合金中的作用、机理及开发生产钼铼合金材料均具一定的参考价值。     

美国铼合金公司开发高能电子管冷源用的钼铼合金

美国铼合金公司 (ＲＡＩ)的Ｄ .Ｂｏｒｉｓ及其同事曾经指出 ,铼含量超过 4 0 %的钼铼合金具有高温强度大、高温塑性好、室温可成形性优良和能够经受住热震等优点 ,人们很有兴趣把它们应用在许多高技术领域中 ;例如 ,用作高能电子管的冷源 ,而深拉伸则是加工这种器件的普通技术。所以 ,评价钼铼合金显微组织和化学成分的影响对这类用途来说是至关重要的。对业已得到的关于Ｍｏ - 41Ｒｅ和Ｍｏ - 48/5 0Ｒｅ合金可成形数据所做的分析表明 ,必须全面探查和研究钼铼合金在这类尖端用途中的潜力。在第 14届国际普兰西研讨会上 ,美国铼合金公司宣…     

低铼钼合金加工性能的研究

研究了粉末冶金法制取的低铼钼合金的加工性能。结果表明，低铼钼合金的抗拉强度和再结晶开始温度，均随着铼含量的增加而提高．在900～1400℃温度范围内，铼含量为1％、3％、5％的钼合金丝样的抗拉强度与退火温度的关系具有显著线性回归特征．     

钼铼合金板材研究

本文对低铼钼合金板材的加工工艺及合金性能进行了研究。用固液混料方法制取钼铢(Mo-Re)混合粉,用H_2烧结制取Mo-Re合金坯,采用煅造开坯、热轧、冷轧的加工工艺生产0.2mmMo-Re合金板材。M05Re合金抗张强度大于1500MPa,最大负荷为100kg时的杯突深度为0.2mm。钼铼合金的电阻率随铼含量增加有规律地增加。     

高Ta钛合金在沸腾硝酸中的腐蚀行为

对高Ta含量钛合金Ti-32Ta在8 mol/L沸腾硝酸溶液中进行了全浸腐蚀实验,研究了Ti-32Ta合金在沸腾硝酸中的腐蚀行为。采用扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线衍射光电子能谱(XPS)等分析方法对钛合金腐蚀表面的钝化膜进行了成分、组织结构及合金价态分析。结果表明:Ti-32Ta合金在沸腾硝酸溶液中呈现均匀腐蚀行为,在介质中通入一定流量的新鲜空气对合金稳定腐蚀阶段的腐蚀速率影响不大。与Ti-6Ta合金相比,Ti-32Ta合金腐蚀后形成的钝化膜更薄更致密,耐蚀性能更好。两种合金腐蚀钝化膜中Ti和Ta的价态组成相同,Ti-32Ta合金腐蚀表面Ta及Ta2O5的含量高于Ti-6Ta合金腐蚀表面。     

Ti-Mo-Sn形状记忆合金管在微导尿管上的应用

Recently, minimally invasive surgeries using guide-wire, catheter, stent etc. have spread rapidly as the diagnosis and the medical treatment for a cancer, a disease in a circulatory organ etc. Currently, further maneuverability and functionability of those devices are strongly desired in order to be used widely and safely. Although Ti-Ni shape memory alloys have been used in medical devices such orthodontic wire, guide-wire, it has been suspected that Ni is allergenic and carcinogenic to the human body. Thus the development of Ni-free shape memory alloys has been strongly required. Re- cently, several Ni-free beta-titanium alloys such as Ti-Mo-Al, Ti-Mo-Ga, Ti-Nb-Al have been developed as new-type shape memory alloys. We have been studying Ti-Mo based beta-titanium alloys and Ti-Mo-Sn alloy has constantly superelasticity of 3%. The purpose of present study is to propose the micro catheter with thin wall and high flexibility using To-Mo-Sn alloys tube on the basis of its mechanical properties.     

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Effect of tantalum (Ta) on strengthening and the relevant mechanism of Fe-C-Ta alloy were preliminarily studied by mechanical property testing and OM, SEM, TEM observation. The results show that the strength of the alloy can be improved greatly as the Ta content is increased from 0. 027% to 0. 059% while the impact energy is reduced 87J. However, the alloy with higher Ta content (0. 059%) still behaves better toughness. It was analyzed that both solution strengthening and precipitation strengthening are the main strengthening effects of Ta on the alloy. Both strength and plasticity of the alloy with higher Ta content (0. 059%) reach the optimum values after aging at 600?? for 1h due to the precipitations of the Ta contained carbides.     

真空等离子喷涂HA/Ta复合涂层

羟基磷灰石(HA)具有良好的生物相容性和骨传导能力,采用等离子体喷涂技术在钛合金等金属基材上制备的HA涂层材料已在临床医学上被广泛使用。但是,HA涂层与钛合金基材之间较低的结合强度影响了植入物在体内的长期使用。本文采用真空等离子体技术制备钽(Ta)掺杂的HA涂层,以期在保持其良好生物学性能的同时提高其结合强度。HA/Ta复合涂层的微观形貌、元素组成和相组成由SEM及配套的能谱仪(EDS)和XRD分析技术表征。按ASTMC-633标准对涂层的结合强度进行了测试。将涂层试样浸泡于模拟体液中以评估其生物活性。结果表明:Ta增强HA涂层具有粗糙的表面和层状结构,其结合强度随着Ta含量的增加而增加。掺60%Ta(H4T6)涂层的结合强度达到37.2MPa,约为HA涂层的1.9倍。模拟体液浸泡试验显示,掺钽HA涂层表面形成了类骨磷灰石,表明具有良好的生物活性。     

德国形状记忆合金的研究与开发

本文综述了德国形状记忆合金的研究与开发现状，重点介绍了近年来在形状记忆合金领域的研究中心和研究重点，评述了形状记忆合金在汽车业、医学界等方面的应用状况，展望了该合金应用方面的发展前景。     

稀土铝添加剂在热浸镀锌中的应用试验

研究了稀土铝添加剂在热镀锌中的应用效果。结果表明当锌浴中加入一定量的镧铈稀土(其含量为0．05％)和铝(其含量为0．10％)，可显著提高热镀锌层光亮性，使锌镀面的耐蚀性提高1倍，锌液粘度降低，锌附着力增强，使镀层减薄32％，减少锌浴表面氧化，锌渣量下降，降低成本，且明显降低热镀锌浴温。     

Production of Integrated Automotive Part in High Pressure Diecasting Process Using Salt Core

A new concept of salt core, a melting temperature of which is lower than the solidus temperature of cast alloy,was introduced to produce an integrated casting part having a complicated inner shape or requiring under-cut in high pressure die casting or squeeze casting process. A salt core, named a fusible core in this paper because the salt core can be easily extracted just as holding at a temperature under a solidus temperature of a casting alloy, was developed and applied to produce a fuel control part for automotive GDI engine in high pressure diecasting machine. A different salt material of a lower melting temperature than that of A1 alloy was mixed with a different ceramic particulate to improve a thermo-physical property of fusible core. The thermo-physical property of the fusible core was measured and a weight faction of the ceramic particulate was optimized. The selected core materials were poured in metallic mold by gravity to produce a fusible core for a fuel control part for automotive GDI engine. The fuel control part, which the fusible core was included inside, was successful to fabricate in a conventional diecasting machine with no melting of fusible core during casting.     

Structural Analysis,Electrochemical Behavior,and Biocompatibility of Novel Quaternary Titanium Alloy with near β Structure

This article analyses the microstructure, electrochemical behavior, and biocompatibility of a novel Ti-20Nb-10Zr-5Ta alloy with low Young’s modulus (59 GPa) much closer to that of bone, between 10 and 30 GPa, than Ti and other Ti alloys used as implant biomaterial. XRD and SEM measurements revealed a near β crystalline microstructure containing β phase matrix and secondary α phase, with a typical grain size of around 200 μm. The corrosion behavior in neutral Ringer solution evidenced: self-passivation behavior characterizing a very resistant passive film; an easy passivation as a result of favorable influence of the alloying elements Nb, Zr, and Ta that participate with their passive oxides to the formation of the alloy passive film; low corrosion and ion release rates corresponding with very low toxicity. In MEM solution, the novel alloy demonstrated very high corrosion resistance and no susceptibility to localized corrosion. Biocompatibility was evaluated on in vitro human osteoblast-like and human immortalized pulmonary fibroblast cell (Wi-38) lines and the new Ti-20Nb-10Zr-5Ta alloy exhibited no cytotoxicity. The new Ti-20Nb-10Zr5Ta alloy is a promising material for implants due to combined properties of low elastic modulus, very low corrosion rate, and good biocompatibility.     

The effects of replacing the refractory elements W,Nb, and Ta with Mo in nickel-base superalloys on microstructural,microchemistry, and mechanical properties

The effects of an atom-for-atom substitution of Mo for Ta, Nb, or W on the mechanical properties of three typical nickel-base superalloys are discussed relative to the changes in the composition of the γ, γ′, and carbide phases. W partitions to they phase in the IN738 alloy system, but to the γ′ in the U710 alloy. In addition, Mo was found to be more soluble in either the γ or γ′ phase when W partitioned to that phase. Ta, and possibly Nb, decreases the solubility of Mo in the γ′ phase. Mo was found to be a greater antiphase boundary strengthener than W. However, initial data indicate that Mo does not strengthen the γ′ phase as much as Ta. The substitution of Mo for W had detrimental effects on the elevated temperature yield strengths of the modified U710 and IN738 alloys as well as on the creep-stress rupture resistance of the IN738 alloy. The substitution of Mo for Ta also decreased the creep-stress rupture resistance of the modified B1900 alloy. Formerly with Columbia University     

Prediction of equivalent environments by energy exchange and assessments of physiological strain and discomfort

The described equivalence postulate was confirmed experimentally by examining physiological responses as well as discomfort sensation in a series of predicted equivalent conditions during exercise (congruent to 3 met). ET or the equivalent Ta at 50% RH is a single independent variable that is uniquely related to the mean skin temperature (Tsk), skin wettedness (w), body core temperature (Tcore) and sense of discomfort.