WC-Co合金断裂行为行径的观察和分析

结合WC-Co硬质合金工业生产中的质量检测工作,应用OLYMPUSPMG3型光学显微镜和JCXA-733型电子探针显微分析仪的综合功能,较全面地观察和分析了该合金的断裂行为行径,断裂源的走向扩展,裂纹的行径,孔隙、夹杂物成分及周围组织结构。阐述了影响该合金断裂强度的重要结构因素,提出了断裂机理。     

WC—Co—Ni硬质合金断裂行为的观察与分析

结合ＷＣ－Ｃｏ－ＮＩ硬质合金工业生产中的质量检测工作，采用光学显微镜和ＪＣＸＡ－７３３型电子探针显微分析仪，应用二次电子图像（ＳＥＩ），背散射电子图像，特征Ｘ射线扫描图象，观察和分析了该合金的断裂行为，讨论了降低合金强度的因素。     

WC－Co－Ni硬质合金的微观组织和断裂强度

结合ＷＣ－Ｃｏ－Ｎｉ硬质合金工业生产中的质量检测工作，应用二次电子图像（ＳＥＩ）、背散射电子图像和特征Ｘ射线扫描图像，观察和分析了该合金的断裂行为，并讨论了降低合金断裂强度的因素。     

Co－Cr_3C_2合金与WC润湿性的观察和分析

采用实况采相观察了Ｃｏ－Ｃｒ３Ｃ２合金与ＷＣ的润湿现象，采用ＪＣＸＡ－７３３型电子探针显微分析仪和３０１４型Ｘ射线衍射仪研究了Ｃｏ－Ｃｒ３Ｃ２合金熔渗ＷＣ所形成的组织，为ＷＣ－Ｃｏ合金中添加Ｃｒ３Ｃ２的作用机理提供解释依据。     

Co—Cr3C2合金与WC润湿性的观察和分析

采用实况采相观察了Ｃｏ－Ｃｒ３Ｃ２合金与ＷＣ的润湿现象，采用ＪＣＸＡ－７３３型电子探针显微分析仪和３０１４型Ｘ射线衍射仪研究了Ｃｏ－Ｃｒ３Ｃ２合金熔渗ＷＣ所形成的组织，为ＷＣ－Ｃｏ合金中添加Ｃｒ３Ｃ２的作用机理提供解释依据。     

Fe—Cr—Co永磁,半永磁合金

本文简要介绍了Ｆｅ－Ｃｒ－Ｃｏ合金的主要特点。回顾了该合金国内外发展历程。多方面讨论了其牌号，工艺、结构、磁性能以及目前开发应用状况     

新型纳米晶合金Fe69.5Cu0.5Cr4V5Si13B8退火过程中微结构的Mossbauer

采用Ｍｏｓｓｂａｕｅｒ、Ｘ－射线衍射等实验方法研究了新型纳米晶合金Ｆｅ６９．５Ｃｕ０．５Ｃｒ４Ｖ５Ｓｉ１Ｂ８退火过程中微结构的变化，实验结果表明，该合金经５４０℃退火４０分钟后能获得优良的综合软磁性能，此时，合金形成双相结构，即具有ＤＯ３型超点阵结构的α－Ｆｅ（Ｓｉ）固溶体超细颗粒和作为晶界的富Ｃｒ、Ｖ、Ｂ等元素呈弱铁磁性的非晶相。超细颗粒的尺寸为２０ｎｍ左右。当退火温度超过６００℃后，残余的非晶     

新型耐磨耐热不锈钢GX－10

研制了一种新型１．１Ｃ－１４Ｃｒ－５Ｃｏ－４Ｍｏ－１Ｖ合金（ＧＸ－１０），该合金室温ＨＲＣ６０，５５０℃ＨＲＣ５５，具有高的耐磨耐热耐蚀性能和低的线膨胀系数，ＧＸ－１０合金适于制造５５０℃高速运转的精密偶合部件。     

WC－Co合金的强度与韧性的关系

ＷＣ－Ｃｏ合金的强度与韧性的关系（日）贞孟史，荞麦田薰关于ＷＣ－Ｃｏ合金的抗弯强度Ｇｕｒｌａｎｄ等人早已研究了组织因子（Ｃｏ量，ＷＣ粒度，内孔隙）的关系。由于某些内孔隙影响最大抗弯强度值，且其周围的破坏机理也截然不同。可是，抗断裂试验的破坏都是由破坏...     

Ni－Mo－W型铸造镍基合金的组织及其耐蚀性的研究

本文研究了Ｎｉ－Ｍｏ－Ｗ型铸造镍基合金的组织及其耐蚀性能。该合金在３０－３６％ＨＣｌ，６０℃苛刻条件下，与性能优良的ＨａｓｔｅｌｌｏｙＢ－２合金做了对比试验。着重研究了Ｗ对题述合金组织与耐蚀性能的影响。试验结果表明，适量的Ｗ可明显提高合金耐浓盐酸介质的均匀腐蚀性能，并使合金具有较好的电化学腐蚀性能和较高的抗点蚀性能。     

粉末冶金法制备CrFeNiCuMoCo高熵合金的组织与性能

利用粉末冶金法制备CrFeNiCuMoCo高熵合金,用带有能谱的扫描电子显微镜(SEM/EDS)、X射线衍射仪、显微/维氏硬度计、电化学工作站、材料试验机等对CrFeNiCuMoCo高熵合金组织结构进行分析并测试其硬度、耐蚀性和压缩性能.结果表明:CrFeNiCuMoCo高熵合金组织形貌简单;物相主要由FCC和BCC两相组成,Mo元素和Cu元素在合金中存在偏析现象;合金的耐蚀性能优异,与304不锈钢相比,自腐蚀电流密度减小1个数量级;组元间原子半径的差异导致较大的晶格畸变,阻碍位错的运动,使得固溶强化效应增强;Mo元素起到细化晶粒作用,使该合金具有较高的硬度和抗压强度,合金硬度为485 HV,抗压强度约为1 385MPa;断裂类型为脆性解理断裂.     

Dy含量对Mg—Dy—Nd合金组织与力学性能的影响

探讨了稀土元素Dy含量对Mg—Dy—Nd合金力学性能与组织的影响变化规律。力学性能测试结果表明随着Dy元素含量的增加，合金抗拉强度几乎成直线增加，屈服强度有不明显增加，塑性变型降低明显。采用扫描电子显微镜及晶相显微镜分析了不同Dy含量下，Mg-Dy—Nd合金的微观形貌及组织形态，初步分析了该合金的断裂机理。     

Ultrafine high-cobalt hard alloys. II. Connection between mechanical properties and structure

The experimental dependences of strength, plastic properties, hardness, and fracture toughness on sintering or pressing temperature for ultrafine alloy WC-41 wt.% Co are presented. The alloy densifies in solid phase and temperature varies from 950 to 1250°C. The dependences of mechanical properties are extreme, excepting fracture toughness. The properties reach their maximum values at 1050 to 1150°C depending on the type of testing. Fracture toughness continuously increases with densification temperature. The highest values of some properties are reached after additional solid-phase annealing. The mechanical properties of ultrafine high-cobalt alloy samples are assessed with the use of structural parameters and empirical equations established for standard hard WC-Co alloys sintered in liquid phase. The calculated and experimental values of properties differ: transverse rupture strength, fracture toughness, and yield strength show higher values, while hardness and compressive strength have lower values as compared with calculated ones.     

Effect of water and artificial saliva on the low cycle fatigue resistance of cobalt-chromium dental alloy

STATEMENT OF PROBLEM: Fatigue of denture clasp alloys causes clasp failures and decreases the retention of removable partial dentures. Little information is available on how the environment (dry, water, artificial saliva) effects the fatigue behavior of cast cobalt-chromium alloy clasps. PURPOSE: This study determined the effect of water and the artificial saliva on the resistance of cast cobalt-chromium alloy to the deflection fatigue. MATERIAL AND METHODS: Test bars (n = 10) were tested either dry, in water, or in artificial saliva (Fusayama type) with a constant deflection fatigue test. The number of loading cycles before fracture was registered as resistance to fatigue. To establish whether there were indications of alloy corrosion occurring during the fatigue test, the testing liquid was analyzed retrospectively with an atomic absorbance spectroscopy. To determine elemental composition of the fracture surface, fracture surfaces of the test bars were analyzed with a scanning electron microscope and energy dispersive spectroscopy. RESULTS: The bars that were tested dry had a mean fatigue resistance of 78,000 loading cycles, whereas test specimens tested in artificial saliva had a resistance of 59,000 loading cycles and 36, 000 for those tested in water. Atomic absorbance spectroscopy revealed small amounts of cobalt (Co) in testing water and in artificial saliva. Energy dispersive spectroscopy analysis revealed differences in elemental composition of a fatigue fracture surface compared with that of a 1-bend fracture. CONCLUSIONS: The results suggest that both water and artificial saliva reduce the fatigue strength of cobalt-chromium alloy, explained by corrosion of the alloy in the wet environment.     

Hydrogen embrittlement of ultra-pure alloys of the inconel 600 type: Influence of the additions of elements (C,P, Sn,Sb)

The mechanical behavior of very high purity nickel base alloys of the Inconel 600 type that were simultaneously charged with hydrogen and deformed in tension was investigated. Experimental results show that this procedure decreases markedly the fracture strain of the pure 76 pct Ni-16 pct Cr-8 pct Fe alloy; cracks are observed after two to four pct elongation, and the fracture is completely intercrystalline. Hydrogen embrittlement appears as an intrinsic property of the Ni-Cr-Fe system in the sense that the grain boundary cohesion decreases when the purity of the alloy increases. The presence of carbon or phosphorus in the alloys increases grain boundary cohesion. The addition of metallic elements such as antimony or tin has relatively little effect on intergranular embrittlement.     

THE EFFECT OF GRAIN-BOUNDARY STRUCTURE ON THE TENSILE FRACTURE BEHAVIOUR OF HOT-ISOSTATICALLY PRESSED 713LC ALLOY COMPACTS

Abstract

Examination of the ambient-temperature tensile fracture behaviour of hot-isostatically pressed 713LC alloy compacts indicates that the nature of the fracture paths varies with the thermal history of the material. The fracture mode may be transgranular, interparticle, or intergranular and is apparently controlled by the structures of the grain boundaries and powder-particle boundaries. Interparticle fracture, observed after certain pressing and heat-treatment operations, can be regarded as a variant of conventional intergranular fracture. This type of fracture mode results from the formation of heavy growths of mixed MC + M₂₃C₆ carbide on powder-particle boundaries during processing.     

铍铝合金室温拉伸及原位疲劳失效分析

通过室温拉伸试验和SEM原位疲劳测试,研究了金属型复合材料铍铝合金的拉伸性能及拉伸和原位疲劳的断裂机制.结果表明,合金在室温下具有较好的拉伸性能,且对应变速率有明显的敏感性.拉伸断裂是由脆性铍相的解理断裂和韧性铝相的延性断裂构成的混合型断裂.在拉拉疲劳载荷下,疲劳裂纹萌生于铍相颗粒,断裂模式仍由铍相的解理断裂和铝相的韧性断裂组成.     

室温大气环境下欠时效态3J21合金的拉伸性能

在万能拉伸试验机上对室温大气环境下欠时效态3J21合金的拉伸性能进行研究,并采用金相显微镜、X射线衍射仪对欠时效态金相组织及物相进行分析,采用TEM对固溶态、欠时效态试样及拉伸断口附近形变的显微组织进行分析,采用扫描电镜（SEM）对拉伸断口进行观察。结果表明,室温大气环境下欠时效态3J21合金的拉伸断口为韧窝断口,断口附近显微组织中滑移线之间的距离较小。欠时效态3J21合金具有较好的强度和塑性配合。同时讨论了室温大气环境下欠时效状态对3J21合金拉伸性能的影响。