WC—Co硬质合金中TaC,Cr3C2添加剂的作用机理

研究了添加剂ＴａＣ、Ｃｒ３Ｃ２对ＷＣ－１０Ｃｏ合金组合结构和性能的影响及相关机理。结果表明，添加少量ＴａＣ（ｗ＝２％）、Ｃｒ３Ｃ２（ｗ＝０．４４％）可导致ＷＣ－１０Ｃｏ合金的ＷＣ晶粒明显细化、ＷＣ邻接度下降、γ相平均自由程减小，但强韧性有所下降；Ｃｒ３Ｃ２助长ＷＣ－１０Ｃｏ合金ＷＣ晶粒断续长大；ＴａＣ－ＷＣ固溶体耐碱蚀性差；合金断口中沿ＷＣ－ＷＣ晶界脆断比例增加，ＴａＣ－ＷＣ固溶体晶粒倾向于穿晶劈     

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。     

WC－Co硬质合金的矫顽磁力

研究了γ相分布和淬火处理对ＷＣ－Ｃ０合金矫顽磁力Ｈｃ的影响规律和机理。结果表明：ＷＣ－Ｃ０合金Ｈｃ与γ相分布有着密切关系，其随合金中Ｃｏ％和ｄｗｃ增加而降低的程度在低Ｃｏ合金范围内符合线性规律，在高Ｃｏ合金中则平缓降低，这是由于ＷＣ邻接度Ｃｗｃ－ｗｃ对γ相磁畴在反磁化过程中的阻滞作用的影响；淬火处理提高ＷＣ－Ｃｏ合金的Ｈｃ主要是由于淬火对γ相成分和应力状态的影响。     

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。     

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。     

硬质合金的硬度和矫顽力及其相互关系

探讨了硬质合金的硬度、矫顽力同合金显微结构和成分的关系，得到了两相高碳ＷＣ－Ｃｏ硬质合金的比矫顽力Ｈｓｃ，和维氏硬度ＨＶ间关系的实验规律；Ｈｓｃ＝１．１６＋「（１８９７／ＨＶ）－３．３１」＾－１。论述了有关物理基础，讨论了用Ｈｓｃ对ＷＣ－Ｃｏ合金的ＨＶ进行评估的可能性。     

用磁性法测定两相WC—Co硬质合金的碳含量

论述了用４πσ测定两相ＷＣ－Ｃｏ硬质合金碳含量的方法和原理。结果表明，用４πσ鉴定ＷＣ－Ｃｏ合金碳含量的两相区范围作为质量控制目的切实可行。由于影响４πσ的因素较多，精确测定ＷＣ－Ｃｏ合金两相区内碳含量需要预先确定试样的结构状态，并作出相应状态下的合金４πσ－Ｘｃ校准曲线，测定精度为万分之二。     

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。     

用磁性法测定两相WC－Co硬质合金的碳含量

论述了用４πσ测定两相ＷＣ－Ｃｏ硬质合金碳含量的方法和原理。结果表明，用４πσ鉴定ＷＣ－Ｃｏ合金碳含量的两相区范围作为质量控制目的切实可行。由于影响４ｎσ的因素较多，精确测定ＷＣ－Ｃｏ合金两相区内碳含量需要预先确定试样的结构状态，并作出相应状态下的合金４πσ－Ｘｃ校准曲线，测定精度为万分之二。     

超细晶粒WC—Co硬质合金的剪切模压成型工艺

采用剪切模压新工艺成型,通过真空烧结制备出了超细晶粒ＷＣ－Ｃｏ硬质合金。研究了不同成型剂的特性、成型剂的配比、加入量以及压制力对剪切模压成型的影响。研究结果表明,采用剪切模压成型工艺可获得很高的成型质量,从而制备出具有较好物理力学性能的超细ＷＣ－Ｃｏ硬质合金。     

共沉淀回收硬质合金的碳含量控制

本文揭示了共沉淀回收WC－Co复合粉末的特性，探讨了用这种回收粉末制备的再生硬质合金的碳含量控制．结果表明，该回收料的还原粉末中的Co以Co3W和Co7W6化合物形式存在，是导致再生合金中WC晶粒缺隐、不连续长大粗晶WC存在和出现η相的原因；采用适当工艺规范以真空烧结可有效地对再生硬质合金进行碳含量控制．     

WC颗粒增强铜基合金覆层用钎料的研究

研制了一种新型钢用WC颗粒增强铜基合金覆层用的CuMnNiCr多元铜基钎料,对该钎料的熔化特性、钎料组织、钎焊工艺及力学性能进行了研究,并通过优化的钎焊表面合金化工艺,在普通铸钢件表层制得了WC颗粒增强铜基合金耐磨覆层.研究结果表明,与普通的CuZnNi、CuMnNi合金钎料及NiCrBSi高温自熔合金钎料比较,CuMnNiCr多元合金钎料由于多种强化机制而具有优良的综合力学性能.此外,该钎料还具有优异的钎焊冶金特性、致密的冶金结合界面以及较高的界面结合强度.使用该钎料制备的复合覆层具有良好的综合性能.SEM,EDS及XRD分析表明:该复合覆层与钢母体结合牢固;覆层内合金基体与WC颗粒形成了冶金结合,WC的体积分数可达54%,复合覆层组织由α-Cu固溶体基体、α-Cr与MnNi弥散硬化相及WC硬质相组成.磨损实验证明,该覆层的耐磨性远优于30MnSiTi马氏体低合金钢.     

钎焊法制备硬质颗粒复合材料的耐磨性和磨损机理

为了提高硬质颗粒复合合金材料的耐磨性并揭示其与界面结合、微观组织及磨损机理之间的关系,本文设计并通过钎焊法,在普通铸钢件表面制得了厚度可达30mm的WC颗粒增强铜基合金覆层,测试分析了上述各种因素对此覆层耐磨性的影响.力学性能测试表明:该覆层与钢母体结合强固,且具有良好的综合性能.SEM观察和能谱分析说明:复合合金层组织由弥散强化铜基合金基体与WC颗粒相组成,且二者形成了强有力的反应性结合.磨料磨损试验证明:该复合合金在二体和三体磨损条件下均有较高的耐磨性,与低合金钢的切削和犁沟变形应变疲劳以及高铬铸铁的切削磨损机理不同,该复合合金与切削及脆性剥落两大磨损机理相对应.     

Analysis of Formation and Interfacial WC Dissolution Behavior of WC-Co/Invar Laser-TIG Welded Joints

During the valve fabrication, hard metal is welded to stainless steel or invar alloy for sealing purposes because of its good heat resistance operating at 500 °C. However, WC (tungsten carbide) dissolution in weld pool softens the hard metal and decreases mechanical properties near the hard metal/weld interface. In order to analyze the WC dissolution in welded joint, joining of hard metal and invar alloy was carried out using laser-tungsten inert gas hybrid welding method. Microstructures of the weld region, chemical composition were investigated using optical microscope, scanning electron microscopy, and EDAX, respectively. Mechanical properties such as microhardness and four-point bend strength test were performed. Larger and smaller WC dissolution and WC dissolution through transition layer based on thermo-dynamics were discussed. The results thus indicate that WC dissolution led to cellular microstructure, columnar crystal, and transition layer under the effect of laser beam and tungsten arc. WC dissolution was affected by metal ions Fe⁺, Ni⁺, Co⁺ exchange in W-M-C system, and WC grain growth was driven by forces caused by laser beam and tungsten arc in larger WC, smaller WC, and liquid Fe, Ni systems.     

钨钴复合粉在流态化床中的碳化反应过程研究

将钨钴复合氧化物置于自主研发的高温流态化床中,采用氢气作为还原剂,经过还原反应后得到类金属化合物-钨钴复合粉(Co7W6和W),再加入炭黑进行碳化反应,得到最终产品碳化钨钴复合粉。试验过程进行实时在线取样,对样品进行相组成和Co、C、O、N等元素含量分析。研究结果发现,碳化过程非常迅速,其中类金属化合物Co7W6按照Co7W6→Co6W6C→Co3W3C→WC进行碳化,单质金属W是按照W→W2C→WC进行碳化,并且W2C比Co3W3C更易碳化。同进还发现,不需要经过CoW3C相可以实现完全碳化。     

In-situ metal binder-phase formation to make WC-FeNi Cermets with spark plasma sintering from WC,Fe, Ni,and carbon powders

High-density WC-FeNi ceramic-metal (cermet) composites were fabricated using liquid-phase spark plasma sintering/field-assisted sintering technology (SPS/FAST) with in-situ formation of metal binder phase. The precursor materials were micron-sized powders of WC, Fe, Ni, and C. A low melting point from a eutectic reaction of the powders enabled the in-situ formation of FeNi alloy and facilitates liquid-phase sintering of the WC. The carbon powder was added to stabilize the formation of the binder phase. Electron backscatter diffraction (EBSD) was performed to measure grain size and orientation. The composite exhibited a 99% theoretical density and a microstructure consisting of rounded and contiguous WC grains. The average grain size is 10.5 μm. The composite has a maximum hardness of 16.1 GPa. This research provides a fast and cost-effective approach to fabricate hard metals.     

Wear-resistant WC composite hard coatings by brazing

A wear-resistant tungsten carbide/copper (WC/Cu) brazing alloy coating was deposited onto a steel substrate by high-temperature furnace brazing. Compared with other hard surfacing processes, much larger WC particles could be used to make a metal layer with higher wear resistance. ASTM G-65 wear test results for the brazed composite coating showed a higher wear resistance when compared with some WC-Co hard coatings that are commonly used. In this paper, the brazing alloy, the brazing process, and the after-brazing heat treatment are studied. The microstructure of the brazing alloy and the as-deposited coating were characterized, and no significant porosity was found. A good metallurgical bond was formed at the WC/Cu alloy interface and at the composite coating/substrate interface. Little or no dilution was observed. The bond strength between the Cu alloy and substrate is also much higher than for a thermal spray coating. This paper was presented at the 2nd International Surface Engineering Congress sponsored by ASM International, on September 15–17, 2003, in Indianapolis, Indiana, and appeared on pp. 592-96.     

高Ni钎料-WC硬质合金颗粒复合堆焊焊条的探讨

以SiC材质成型舟皿作为模具,尺寸为2～5 mm的YG8型WC硬质合金颗粒为耐磨相,CuZnNi合金为胎体金属,加入NiCrBSi合金粉末以提高胎体金属的Ni含量与Cr含量,采用钼丝氢气炉烧结制备高Ni钎料-WC硬质合金颗粒复合堆焊焊条,并对成型后焊条的断面形貌及胎体金属成分进行分析.结果 表明,硬质合金颗粒在焊条内呈...     

Effect of the high energy milling on the microstructure of Cu-20%WC composite powders prepared with recycled WC

A mixture of Cu-20wt%WC was milled in a high energy mill for up to 50 h. The WC powder was recycled from hard metal scrap. It presents agglomerates of faceted WC particles and residual Co and Fe. In the first hours of milling, the Cu particles are deformed into plates, the agglomerates of WC are broken apart, the primary WC particles are fragmented and embedded in the Cu phase. Composite particles are formed. As milling proceeds, different plates are welded together and folded. The particle size increases. However, the hardened Cu becomes fragile and begin to break, decreasing the particle size. Both, Cu and WC are under compressive strain. Residual Co and Fe present in the recycled powder are dissolved in Cu and behave like the soft Cu phase.     

高熵合金/碳化钨复合材料的研究进展

综述了高熵合金(HEA)/碳化钨(WC)复合材料研究进展,主要介绍了以WC为基体的WC-HEA硬质合金和以HEA为基体的HEA/WC复合涂层,探究了高熵合金复合碳化钨材料强度、硬度、耐磨性、耐腐蚀性能提高的方式,并展望了高熵合金与WC相复合的发展前景与研究开发的重点。