硬质合金冷拔模强化处理研究

研究了WC-Co硬质合金，特别是YG25牌号硬质合金的渗硼淬火与深冷处理强化工艺和不同含量的合金强化处理效果，并对强化机理进行了讨论。     

硬质合金冷拔模强化处理研究

研究了WC-Co硬质合金,特别是YG25牌号硬质合金的渗硼淬火与深冷处理强化工艺和不同含量的合金强化处理效果,并对强化机理进行了讨论。     

WC－20Co硬质合金钎焊的热处理机理

研究了高频钎焊同时淬火处理对ＷＣ－２０Ｃｏ硬质合金刀片显微结构和性能的影响。结果表明，在１０００～１２００℃温度范围内处理将导致ＷＣ－２０Ｃｏ合金刀片中ＷＣ相邻接度∑ＷＣ－ＷＣ下降、ｒ相平均自由程Ｌ＿ｒ增加、韧性改善和硬度提高等一系列淬火效果。断口形貌微观特征也表明了合金韧性的提高。当处理温度超过１２００℃后，ＷＣ－２０Ｃｏ合金的显微结构和性能将恶化。     

WC-20Co硬质合金钎焊的热处理机理

研究了高频钎焊同时淬火处理对ＷＣ－２０Ｃｏ硬质合金刀片显微结构和性能的影响。结果表明，在１０００－１２００℃温度范围内处理将导致ＷＣ－２０Ｃｏ合金刀片中ＷＣ相邻接度∑ＷＣ－ＷＣ下降，γ相平均自由程Ｌγ增加，韧性改善和硬度提高等一系列淬火效果。断口殂貌微观特征也表明了合金韧性的提高。当处理温度超过１２００℃后，ＷＣ－２０Ｃｏ合金的显微结构和性能将恶化。     

我国钛合金的发展现状──评第八届全国钛合金学术交流会

探讨了淬火热处理对ＷＣ－ｃｏ硬质合金性能影响的机理。查明了淬火既改变ＷＣ－ＣＯ合金γ相的成分和合金的应力状态，也改变合金的显微结构参数（其变化程度与ＷＣ的平均晶粒度有关）。考查了Ｗｅ－Ｃｏ合金淬火效果在合金制品实际应用过程中的稳定性从而指出了ＷＣ－Ｃｏ合金淬火热处理的实用意义。     

快速凝固Cu—Cr合金时效析出的共格强化效应

采用单辊快速凝固的方法制备Ｃｕ－Ｃｒ合金微晶薄带,经适当的时效处理,可以在导电率不降低的前提下,显著提高合金的强度和硬度,强度和硬度的提高主要是由晶粒细化和共格弥散析出强化所造成,共格硬化效果与采用Ｇｅｒｏｌｄ公式计算的结果非常接近,与常规固溶处理的Ｃｕ－Ｃｒ合金相比,峰值硬度提高了１．６倍,其中２７％由细晶强化产生,７３％则由时效析出的共格强化提供,固溶强化和空位强化对快速凝固Ｃｕ－Ｃｒ合金强度     

硬质合金深冷处理技术及其发展概况

介绍了国内外硬质合金深冷处理的发展概况和硬质合金的深冷工艺,深冷效果及其强化机理。硬质合金深冷处理后主要提高了材料的耐磨损性能;对硬度、抗弯强度、密度、磁性能等其它物理性能和微观组织的影响不显著但是硬质合金深冷处理后,ε-Co含量和表面残余应力增加,其强化机理主要是相变强化和表面残余应力强化。     

细晶粒WC—VC—Co硬质合金

本论文描述了１０ｗｔ％ＶＣ的ＷＣ－ＶＣ－Ｃｏ硬质合金的生产过程和部分性能，该合金的可烧结性表明比预期的要好，而且硬度比同等钴含量的ＷＣ－Ｃｏ硬质合金要高，韧性优于相同硬度的ＷＣ－Ｃｏ硬质合金。     

电溶解法回收废残WC—Co硬质合金

报导了用电溶解法回收废残ＷＣ－Ｃｏ硬质合金的工艺和实践，分析了电溶解ＷＣ－Ｃｏ硬质合金时反应过程的机理，指出：只要适当控制电解条件，就可以将ＷＣ－Ｃｏ合金进行分离和再生。     

硬质合金锪刀的深冷强化处理

研究深冷处理对YG8硬质合金物理机械性能的影响，选择硬质合金锪刀的强化处理工艺。实验证明：锪刀经深冷处理后，其刃磨使用寿命提高3．7～5倍，取得明显效果。在此基础上，初步探讨了深冷处理对硬质合金锪刀强化的机理。     

Cu-Fe基金刚石锯片刀头真空液相烧结性能研究

采用真空液相烧结的方法，设计了Cu-n基刀头基体配方，以低熔点铜基预合金粉末为粘结相，并添加Ti、Cr等活性金属粉末改善基体与金刚石的结合力，通过组织观察及性能分析，讨论了粘结相．骨架相及活性金属含量对基体及刀头性能的影响。随Ti含量的增加，粘结相对骨架相的润湿能力增强，基体的硬度增加，基体对金刚石的结合力提高，刀头的耐磨性增加。随粘结相含量的增加，基体的合金化及致密性提高、硬度增加．刀头的耐磨性增加；硬质颗粒含量较少时对基体的增强作用是弥散强化，当硬质颗粒形成连续骨架时形成颗粒增强。     

硬质合金热处理机理研究

通过对YT14（WC－TiC－Co合金）、YG15（WC－Co合金）两种合金热处理前后其粘结相、硬质相、应力状态等方面的分析研究，结果发现，合金热处理后，粘结相中Co含量增加，马氏体相变得到抑制，碳化钨晶粒邻接度下降，同时，还改变了合金内部的应力状态。作者从多方面阐述了热处理的强化作用。     

Plastic deformation mechanism in nanotwinned metals: An insight from molecular dynamics and mechanistic modeling

An overview is given of the deformation mechanisms in nanotwinned copper, as studied by recent molecular dynamics, dislocation mechanics and crystal plasticity modeling. We highlight the unique role of nanoscale twin lamellae in producing the hard and soft modes of dislocation glide, as well as how the coherent twin boundaries affect slip transfer, dislocation nucleation, twinning and detwinning. These twin boundary-mediated deformation mechanisms have been mechanistically linked to the mechanical properties of strength, ductility, strain hardening, activation volume, rate sensitivity, size-dependent strengthening and softening in nanotwinned metals. Finally, discussions are dedicated to identifying important unresolved issues for future research.     

Dispersed hard particle strengthening of metals

A review is presented of the various methods utilized to strengthen metals and alloys for high temperature service by a suitable dispersion of finely divided hard particles. Alloys such as SAP, produced by powder metallurgy, and other sintered aluminum powders, molybdenum containing small quantities of refractory oxides and magnesium containing a dispersed intermetallic, are considered. Internal oxidation and other methods of achieving a hard particle dispersion are discussed. New data on the high temperature strength and stability of the alloy systems Cu-Al₂O₃, Ni-Al₂O₃ and Be-Be₂C are shown. The theoretical aspects of the hardening and strengthening mechanism are presented and consideration is given to the problems associated with the powder metallurgy of the various processes.     

Modelling of processes of thermochemical treatment of metals: traditions of Russian scientific school

Abstract

The paper is devoted to 100th anniversary of the outstanding Russian scientist professor Yuriy Mikhailovich Lakhtin – the founder of the world-famous scientific school of surface strengthening of metals and alloys. Lakhtin's scientific school is recognised for its contribution into research of processes of thermochemical treatment of metals and especially of nitriding. Today at the Department of Metal Science and Heat Treatment of MADI his followers continue the traditions of Lakhtin's scientific school. The development of technologies of surface engineering is based on complex modelling of physical processes realised by thermochemical treatment of metals. Thermodynamic models describe the interaction between metals and components of saturating atmosphere and predict phase composition of diffusion layer. Diffusion models of kinetics of saturation of metals allow us to calculate the rate of growth of diffusion layer and regulation of its depth and structure. Structural models determine quantitative dependence between parameters of structure (grain size, dispersed particles, etc.) and mechanical properties. These models allow us to estimate the level of strengthening by control of structural specifics of strengthened layer. On the basis of this complex of models, new efficient technologies of surface strengthening are developed.     

采用动态热模拟技术研究稀土对硬质合金性能稳定性的影响

该文采用动态热模拟技术研究了稀土对硬质合金性能与粘结相结为稳定性的影响，发现以非氧化物方式加入稀土元素能改善合金性能，其主要作用是抑制了粘结相向h．c．p结构的马氏体转变，且在长期热循环效应下保持稳定。而以氧化物方式加入稀土元素，抑制粘结相向h.c．p结构的马氏体转变能力差，在一定的热循环效应下不稳定，随着热循环次数的增加，h．c．p结构相含量增加，区改善合金性能不明显。     

Korrosionsresistente,hochverschleißfeste Hartmetalle

Corrosion and highly wear resistant hard metals Hard metals based on WC-Co have a better combination of mechanical properties compared to WC-Ni grades, but their corrosion resistance is generally poor. Either by variation of the binder phase (Ni, Ni-Cr) or by variation of the carbide phase (grain size) the corrosion resistance of hard metals can be tailored to the specific application maintaining the good mechanical properties of WC-Co-grades. The mechanical, chemical and thermal properties of various hard metal compositions are given. Hard metals of modified composition are used for valve parts, seal rings, nozzles and as wear parts for other applications in chemical industry. By their metallic nature, hard metals are still superior to ceramics in their mechanical strength, although ceramics show in general the excellent corrosion resistance. By optimising the carbide and binder phase in hard metals, improved corrosion resistance together with the good mechanical properties of WC-Co can be achieved.     

V含量及回火工艺对高强钢TIG焊熔敷金属组织性能的影响

采用四种不同V含量焊丝对高强钢板进行钨极氩弧焊试验，焊后对熔敷金属进行640 ℃保温2 h的回火处理. 研究了V含量和回火处理对熔敷金属微观组织及力学性能的影响. 结果表明，焊态及焊后回火态条件下，随着V含量的增加，熔敷金属强度升高，延伸率和冲击功降低，经回火处理后，不含V熔敷金属内晶界处析出M₂C碳化物，而含V熔敷金属内析出弥散分布的VC析出相，焊后回火过程中位错回复引起基体软化的作用高于M₂C及VC的析出强化作用，导致回火后强度降低，断后伸长率冲击吸收能量升高. 细小VC具有阻碍位错运动的作用，导致回火后含V熔敷金属仍保留较高的位错密度. 实际应用中应根据熔敷金属性能要求合理选择V含量及焊后回火工艺.     

激光熔覆颗粒增强金属基复合材料涂层强化机制

选用优化的激光工艺参数,利用激光熔覆工艺在中碳钢表面原位合成硬质陶瓷颗粒增强金属基复合材料涂层,涂层熔覆质量良好。涂层是由粘结金属基体和弥散分布于其中的稳定和亚稳定硬质颗粒增强相组成。激光熔覆涂层相对于中碳钢基体强化效果显著。对熔覆涂层的显微分析表明：涂层中存在细晶强化、硬质颗粒弥散强化、固溶强化和位错堆积强化等强化机制。     

Computer-assisted optimization of cobalt-base alloy compositions

Cobalt-base hard metals are known for their wear and corrosion resistance and also for their ability to retain hardness at elevated temperatures.

Considering the matrix of these alloys it can be predicted that (a) the performance against corrosive media will improve when the Cr content is increased, (b) a higher W content will be advantageous because of its solid solution strengthening effect, and (c) care has to be taken in the course of liquid phase sintering to avoid unwished-for carbides and/or intermetallic phases, because these would be detrimental with respect to mechanical properties of the alloys.

To locate ranges for optimal matrix and carbide compositions thermodynamic calculations with were carried out on the basis of recently published data which were improved by a new optimization routine.

A series of phase diagrams was calculated and the optimal compositions of alloys were derived. Furthermore, calculated transition temperatures and phase compositions of some selected alloys compare reasonably with published experimental results.