TiC含量对激光熔覆Fe基复合涂层组分和性能的影响

采用激光熔覆技术在高锰钢基材上制备了不同TiC含量的Fe基复合涂层,研究了TiC含量对熔覆层组分和性能的影响.试验结果表明,熔覆层化学组分包含奥氏体、M7C3碳化物、TiC析出相和未熔TiC颗粒.随着TiC含量的增加,熔覆层硬度逐步增加,耐磨性能先增加后降低.     

The Effect of Cold Isostatic Pressing of Powder Billets Produced from the VK8 Hardmetal on its Hardness and Phase Composition After Sintering

Powder Metallurgy and Metal Ceramics - The paper examines how cold isostatic pressing (CIP) of powder samples preformed by uniaxial pressing at up to 0.4 GPa influenced the density, coercive force,...     

7055铝合金的化学成分、物相组成及其性能特点

说明了7055合金中Zn、Cu、Mg、Si、Fe和Zr等元素在该合金中的作用或影响;阐述了该合金的物相组成和-αAl、η（MgZn2）、S（Al2CuMg）、T（Al2Zn3Mg2）以及Al3Zr的作用;讲解了基体沉淀相（MPt）、晶界沉淀相（GBP）和晶间无析出带宽度（PFZ）对该合金性能的影响,介绍了该合金的性能特点进而介绍了该合金晶界腐蚀、应力腐蚀和剥落腐蚀的产生机理。总结了该合金化学成分、物相组成与宏观性能的对应关系。     

Microstructure, Chemical and Phase Composition of Chromium Silicide Diffusion Coatings on Carbon Steels

The microstructure, chemical and phase composition of chromium silicide diffusion coatings on steels 20, 45, U8, and U10 are studied. It is established that the phases Cr²³C⁶ and Cr⁷C³ with a silicon content in them of up to 0.25 at.% form at the surface of chromium silicide coatings. The maximum silicon content at 7% in steels 20 and 45 is observed beneath the carbide layer at a depth of 40–50 µm, but for steel U10 it is 1.9% at the carbide layer-matrix boundary. It is shown that the corrosion resistance of chromium silicide diffusion coatings increases markedly compared with uncoated specimens: by a factor of 15–30 depending on the acid used (H₂SO₄, HCl, H₃PO₄, HNO₃, CH₃COOH). There is also an increase in the cavitation resistance of articles with chromium silicide coatings in water and 3% NaCl solution.__________Translated from Poroshkovaya Metallurgiya, Nos. 1–2(441), pp. 23–30, January–February, 2005.     

Tb3NiSi2合金磁相变与磁热性能研究

依据X射线衍射(XRD)与等温磁化曲线和等磁场变温磁化曲线,主要研究了Tb₃NiSi₂合金相结构与磁性相变和磁热性能。XRD表明,采用800℃保温14天,然后炉冷至室温的热处理方法制备的R3NiSi2(R=Tb,Dy,Ho,Er)合金中,主相均为Gd3NiSi2型正交结构(空间群:Pnma,No.62)相,但杂相R5Si3含量存在差异,其规律是从Er到Tb,含量依次减少,Tb₃NiSi₂合金样品基本为一个单相,其相应晶格常数分别为a=1.1240(8)nm,b=0.41009(8)nm,c=1.12058(1)nm。等温磁化曲线显示在50~300 K温度范围内,Tb₃NiSi₂合金仅展现出铁磁-顺磁相变,并没有在130,82,66,53 K等观察到相关文献报道的多重的反常反铁磁态-铁磁态(AFM-FM)相变。0.01 T磁场下的磁化强度对温度求导曲线(d M/d T)和0~2 T磁场下的Arrott图结果证实合金铁磁-顺磁二级磁相变居里温度(Tc)=88 K。居里外斯定理拟合表明合金中Tb³⁺粒子的有效磁矩为9.90μB(μB为玻尔磁子),同期望值μeff/Tb³⁺=g(J(J+1))1/2=9.72μB基本一致。在磁热性方面,Tb₃NiSi₂合金在0~2 T磁场范围内,低场响应性较差,铁磁态分子的有效磁矩远低于顺磁分子有效磁矩,最大磁熵变(-ΔSM_max)为3.2 J·kg^-1·K^-1;在对应的半高宽温跨(δTFWHM)=35.5K范围内,相对制冷量为113 J·kg^-1。     

The Phase Composition and Mechanical Properties of Vacuum Coatings Produced from Equiatomic CrFeCoNiMn Alloy

Powder Metallurgy and Metal Ceramics - Mechanical experiments and X-ray diffraction studies of high-entropy vacuum coatings produced by vacuum arc evaporation and sputtering in a compressed...     

Elemental Composition of the Powder Particles Produced by Electric Discharge Dispersion of the Wastes of a VK8 Hard Alloy

The powder fabricated by electric discharge dispersion of the wastes of a VK8 hard alloy is studied by electron-probe microanalysis. This powder formed by electric discharge dispersion in kerosene mainly contains tungsten and carbon and has low contents of oxygen, cobalt, and iron.     

Phase Composition and Wear Resistance of Coatings Formed on the VT6 Titanium Alloy by Plasma Electrolytic Oxidation

Russian Journal of Non-Ferrous Metals - The growth kinetics of the coating during the plasma electrolytic oxidation (PEO) of the VT6 (Ti–6Al–4V) alloy with a specified density of 10...     

Effect of Magnetic-Abrasive Treatment on Wear Resistance of Hard Alloy Inserts with Diffusion Coatings Based on TiC

The mechanism and effect of magnetic-abrasive treatment (MAT) on the wear resistance of WC ― 8 Co hard alloy inserts have been studied. MAT was carried out on hard alloy inserts before and after coating deposition. The results of local x-ray and electron microscopic analyses are discussed. It has been established that a TiC coating deposited by CVD after MAT contains iron inclusions. The transition layer (coating-hard alloy base) is narrower as compared with the literature data and contains more iron than the coating and base. The mechanism of the MAT effect on the wear resistance of inserts with diffusion coatings is proposed. The effect of MAT of insert coatings on their wear resistance is discussed as well. The highest level of strengthening has been achieved by treatment using the following scheme: magnetic-abrasive treatment + chemical vapor deposition + magnetic abrasive treatment (MAT + CVD + MAT).     

化学成分对6082铝合金晶间腐蚀的影响

研究化学成分对6082铝合金晶间腐蚀的影响。结果表明合理控制Mg、Si及Cu元素的含量,能够很好的控制合金的晶间腐蚀。     

Influence of Thermal Cycling Modes on VK8 Hard Alloy Mechanical and Tribological Properties

Russian Journal of Non-Ferrous Metals - Hard alloys are popular materials widely used in the toolmaking industry. The refractory carbides included in their composition make carbide tools very hard...     

搅拌磁场对Ti1023铸锭宏观组织和成分的影响

研究了真空自耗电弧熔炼Ti1023钛合金过程中,搅拌磁场对铸锭宏观组织和铁元素含量的影响。结果表明,熔融金属在没有搅拌磁场的状态下凝固,铸锭的晶粒粗大且中间等轴晶和柱状晶的界线比较明显。施加搅拌磁场后,晶粒变细。磁场对不同熔化阶段的铸锭组织的影响程度不同,在熔炼阶段对组织影响最强,补缩阶段次之,起弧阶段最弱。未施加磁场时,熔池较窄,施加磁场后,熔池变宽,并且铁元素的偏析有一定程度的减轻。     

CVD温度对钽涂层组成、显微组织及形貌的影响

利用TaCl2-H2-HCl反应体系,采用冷壁式化学气相沉积法(CVD)在钼基体表面沉积钽涂层。通过X射线衍射仪、金像显微镜及扫描电镜等手段,对不同沉积温度下钽涂层的组成、组织及形貌进行了研究。结果表明:在1000～1300℃范围内,钽沉积层的相组成无变化,而对择优生长有一定影响;钽沉积层晶粒尺寸随沉积温度的升高而增大;钽沉积层表面颗粒呈金字塔形多面体且随沉积温度的升高而增大。     

稀土钡镁硅铁合金物相和显微组织分析

在成分（ｗｔ％）为ＲＥ２．９１、Ｂａ３．８５、Ｍｇ９．７０：Ｃａ２．２、Ａｌ１．５，余量为Ｆｅ的范围内，运用Ｘ－射线衍射分析及电子探针分析手段对ＲＥＢａＭｇＳｉＦｅ合金的物相和显微组织进行了分析。发现了稀土和碱土金属之间在硅基中的互溶现象并对其进行了初步鉴别。     

Influence of the Chemical Composition and Heat Treatment Modes on the Phase Composition and Mechanical Properties of the ZK51A (ML12) Alloy

The objects of investigation are ZK51A (ML12) alloy samples containing from 3.5 to 5.5 wt % Zn and 0.5–0.8 wt % Zr. The influence of Zn and Zr content on phase transition temperatures and the phase composition in equilibrium conditions and when using the Scheil–Gulliver solidification model is established using the calculation of phase diagrams in the Thermo-Calc program. It is shown that a significant increase in the liquidus temperature of the alloy occurs at a zirconium content in the alloy higher than 0.8–0.9 wt %, and an increase in the melting temperature above 800°C is required, which is undesirable when using steel crucibles. The equilibrium content of alloying components in the magnesium-based solid solution at various temperatures is calculated. The microstructure of as cast and heat-treated alloys with various concentrations of alloying components is investigated using scanning electron microscopy. The distribution of Zn and Zr in a dendritic cell of the as cast and heat-treated alloy is investigated. Zinc is concentrated along the dendritic cell boundaries in the as cast state, but its concentration in their center becomes higher than along the boundaries after heat treatment (HT). Zirconium is concentrated in the center of dendritic cells. It is shown that the two-stage solutionizing mode gives the largest increment of this characteristic: 330°C, 5 h + 400°C, 5 h. The influence of the aging temperature (150 and 200°C) on the sample hardness is investigated. It is revealed that it is higher in the case of aging at 200°C, and its maximum is observed under holding for 8?10 h. The HT of the alloy, including solution treatment (330°C, 5h + 400°C, 5 h) with subsequent quenching and aging (200°C, 8 h), made it possible to attain an alloy ultimate strength of 285 ± 13.5 MPa and a elongation of 11.4 ± 1%.     

热等静压对粉末冶金TiAl 合金显微组织和相成分的影响

采用元素粉末Ti,Al,Cr,Nb为原料,通过对Ar气保护下的高温热压工艺,制备出了高致密度的TiAl基合金。通过光学显微术、SEM、EDAX、XRD技术分析了热等静压对材料的显微组织和相成分的影响。结果表明,在1200℃和1300℃下分别热压1h后可以得到显微组织细小的TiAl基合金,Cr元素的分布比较均匀,但是存在一些Nb元素的扩散不完全现象。通过后序热等静压工艺可以改善合金元素在显微组织中的均匀分布。     

Effect of Chemical and Phase Composition of Sintered Tin Bronzes on Fatigue Failure with Friction

Optical and scanning microscopy together with monitoring the electron work function are used to study the fatigue fracture kinetics of the surface layers of materials in relation to phase composition under severe friction conditions. It is established that periodic variations in the electron work function for rubbing surfaces during fatigue fracture are monoharmonic for homogeneous single-phase materials and polyharmonic for heterogeneous multiphase materials. Depending on the metal-physical features of the materials, additional harmonics may emerge caused by secondary phase inclusions in the spectra for periodic changes in electron work function for rubbing surfaces.