Thermal stability and microstructure development of cast and powder metallurgy produced Mg-Y-Zn alloy during heat treatment

Response to isochronal annealing up to 440 ℃ of squeeze cast Mg–Y–Zn alloy and of the same alloy prepared by powder metallurgy(PM)and extruded at 280 ℃ was studied by resistivity and microhardness measurement,differential scanning calorimetry(DSC)and microstructure investigation.Electrical resistivity was measured at 77 K and microhardness was measured at room temperature after each annealing step.DSC measurement was performed at various heating rates.Transmission and scanning electron microscopy and optical microscopy revealed ribbons of long-period ordered structure(LPSO)18R and planar defects within grain boundaries.Relatively high density of planar defects was found in grain interiors of the cast alloy with the grain size approximately 50μm.Well pronounced subgrains were observed in the PM prepared alloy.Secondary phase particles decorate grain boundaries in this alloy.Three precipitation processes were detected in the cast alloy during repeated isochronal annealing up to 440 ℃,whereas only one significant process was revealed in the PM alloy.These processes were identified as embedding of stacking faults by solutes,development and rearrangement(18R→14H)of LPSO phase and development of grain boundary particles.A coarsening of grain boundary particles rich in Y and Zn only proceeds in the PM alloy.Activation energies of the precipitation processes were determined.Microhardness exhibits good thermal stability against annealing up to 360 ℃ in the PM alloy.

Powder metallurgy processed metal-matrix friction materials for space applications

Owing to the increasing demand for tribological brakes for space applications, the development of novel materials and advanced technologies is necessary. This paper presents the design, characterization, and realization of powder metallurgy processed metal-matrix friction materials intended for the above-mentioned tribological brakes. Selecting appropriate ingredients, which provides an effective way to tailor the properties of the friction material, is evolving as a strategy to meet the design requirements. The tribological behaviors of the friction material are experimentally investigated under different conditions, and special attention is focused on the vacuum tribology. Examinations and analyses of the friction surface and subsurface corroborate the wear mechanism. In addition, the erosion resistances of the friction material are evaluated by exposure tests of ultraviolet irradiation and atomic oxygen. Finally, present and potential space applications of the friction material are also introduced based on experimental studies.

Development of Application of RE Polishing Materials

The manufacturing method and functions of the RE polishing powder and comparation of the current situation of its production and application home and abroad were introduced.By analyzing the development of the liquid crystal (plate) display, the wide application of the RE polishing powder in the field of the liquid crystal display and predicts the development direction of the market of the RE polishing powder was presented.In addition, the development trends of the RE polishing powder industry and forecasts the application prospect of the RE polishing powder was analyzed.

Development of Aluminium Based Hybrid Metal Matrix Composites for Heavy Duty Applications

The present study deals with the investigation of dry sliding wear behavior of aluminium alloy based composites, reinforced with silicon carbide particles and solid lubricants such as graphite/antimony tri sulphide (Sb2S3). The first one of the composites (binary) consists of Al. with 20% Silicon Carbide particles (SiCp) only. The other composite has SiCp and solid lubricants: Graphite + Sb2S3 (hybrid composite) at solid state. Both composites are fabricated through P/M route using “Hot powder perform forging technology”. The density and hardness are measured by usual methods. The pin-on-disc dry wear tests to measure the tribological properties are conducted for one hour at different parameters namely load: 30, 50 and 80N and speed: 5, 7 and 9m/s. The tested samples are examined using scanning electron microscope (SEM) for the characterization of microstructure and tribolayer on worn surface of composites. The results reveal that wear rate of hybrid composite is lower than that of binary composite. The wear rate decreased with the increasing load and increased with increasing speed. The results of the proposed composites are compared with iron based metal matrix composites (FM01N, FM02) at corresponding values of test parameters. These iron based metal matrix composites are also fabricated by P/M route using ‘Hot powder perform forging technology’. The comparative study reveals that the proposed composites have lower friction coefficient, less temperature rise and low noise level;however they have little higher wear rate. It is concluded that the hybrid composite has acceptable level of tribological characteristics with blacky and smooth worn surface.

纳米W-Cu复合粉体制备的研究进展

W-Cu复合材料结合了W、Cu金属各自优良性能,具有良好的高温强度、延展性、抗电弧烧结性、耐高温氧化和低膨胀系数等特点,广泛应用于机械加工、国防工业、航空航天、电子信息、军事等领域。以超细纳米W-Cu复合粉体为原材料是制备出性能优越的W-Cu复合材料的主要途径之一,受到国内外学者的广泛关注。主要总结了W-Cu超细纳米复合粉体的制备方法,如机械合金化法、化学共沉淀法、水热合成-共还原法、喷雾干燥法、溶胶-凝胶法、冷冻-干燥法、燃烧法等,并通过分析现阶段制备W-Cu纳米复合粉体存在的问题,提出了未来该领域的研究方向。

磁性粉末的制备及其在磁性材料中的应用研究

本文介绍了磁性粉末的制备方法,包括物理法、化学法和生物法等。其中,化学法制备磁性粉末的方法最为常用。此外,本文还探讨了磁性粉末在磁性材料中的应用研究,涵盖了磁性材料的制备、性能测试和应用等方面。最后,对未来磁性粉末及其应用的发展进行了展望。

烧结金属粉末多孔材料的应用及发展趋势

烧结金属粉末多孔材料作为一种结构-功能一体化材料,由于其比表面积大、强度高、透过性能优、可焊接且机械加工性能好,因此在近年来得到了迅速发展。介绍了粉末冶金多孔材料的特点及成型工艺,围绕烧结金属粉末多孔元件在过滤分离、粉煤加压流化输送、汽车零部件、流体流量控制和吸声等不同领域的应用,提出了烧结金属粉末多孔材料的发展趋势。

稀土抛光粉产业发展现状与前景

This article briefly introduces the current industrial development status of rare earth polishing powder at home and abroad,summarizes and classifies the types and production processes of existing rare earth polishing powder,analyzes its technical status and existing problems,and the application prospects of rare earth polishing powder.

“双碳”目标下氢冶金发展现状和应用前景

作为支撑我国国民经济发展的基础性行业之一,钢铁行业碳排放总量占全国15%左右,是占比最高的制造业,也是“双碳”目标下工业绿色发展的主战场。目前我国钢铁行业仍以碳排放强度高的长流程为主,粗钢产能约占90%。在双碳目标背景下,“减污降碳”是钢铁行业高质量发展、落实生态文明理念的必然选择。与传统的碳冶金相比,氢冶金可以从源头降低二氧化碳排放量,使钢铁行业摆脱对化石能源的依赖。业界普遍认为,碳达峰碳中和目标下,氢冶金成为钢铁行业实现低碳发展的最为可行途径。本文结合中国钢铁行业特点,分析和展望中国氢冶金的发展模式,进一步提出推动氢冶金发展的相关建议。

粉末冶金技术制备金属多孔材料研究进展

金属多孔材料既有金属的性质,又因为孔的存在,而具有一系列功能特性,诸如密度低、比表面积大、机械强度高、通透性好等,是一种性能优异的多功能工程材料,因而在工程中得到广泛的应用。本文阐述了粉末冶金技术制备金属多孔材料的最新研究进展,主要分析了生物金属多孔材料、形状记忆合金多孔材料、多孔钨电极、多孔不锈钢和多孔铜的制备及研究进展。

粉末冶金γ-TiAl基合金研究的最新进展

γ TiAl基合金是一种具有发展前途的新一代高温结构材料。首先综述了γ TiAl基合金的性能特点和应用前景 ,并简单介绍了该合金的最新基础研究情况。随后介绍了采用粉末冶金方法制备γ TiAl基合金的基本工艺、力学性能 ,最后结合γ TiAl基合金排气阀和板材的研制论述了粉末冶金在γ

铜及铜合金粉末应用及研究现状

本文介绍了近几年国内外铜及铜合金粉末应用及研究现状,并分析了我国同国外先进水平的差距,以及国内目前行业在生产技术、装备和市场等方面存在的问题,为今后行业发展提出了建议。

粉末冶金法制备金属基复合材料的研究及应用

粉末冶金工艺(P/M)具有工艺灵活、可设计性强的特征,是制备高性能金属基复合材料的重要手段之一。简述了P/M法制备金属基复合材料的工艺特点及加工、成型特点,以若干较成功的应用实例为重点总结了粉末冶金金属基复合材料的性能特点,以及国内外的研究与应用现状,提出了该类材料未来的发展方向。

粉末冶金多孔材料新型制备与应用技术的探讨

在归纳分析国内外最近几年金属多孔材料新技术发展的基础上,结合钢铁研究总院采用粉末冶金技术在大尺寸、异型金属多孔元件、等静压制备、多孔金属复合管挤压成型、亚微米不对称复合膜、多孔催化材料和充气模铸等金属多孔材料制备与应用领域的一些进展,围绕能源、石化和煤的洁净加工等应用技术,对粉末冶金多孔材料技术当前发展的问题和特点进行了研究和探讨。

凝胶注模成形技术在粉末冶金中的应用

凝胶注模成形最初是用于陶瓷材料近净尺寸成形技术,它适用于成形件尺寸大,复杂形状的部件。随着该技术的发展,凝胶注模成形也应用到粉末冶金领域。本文综述了国内外凝胶注模技术在成形金属粉末的应用研究近况,展望了该技术在粉末冶金中的应用前景,并对凝胶注模成形技术在应用中存在的技术难点及应对策略进行了分析与探讨。

现代粉末冶金材料和技术发展现状(一)

概述现代粉末冶金材料和技术的发展现状。介绍了传统粉末冶金材料与先进粉末冶金材料的基本特性、应用情况及发展趋势,较系统介绍了机械合金化、粉末注射成形、温压成形、喷射成形、微波烧结、放电等离子烧结、自蔓延高温合成、烧结硬化等新技术的研究与开发状况。内容分(一)、(二)两部分,分两期发表。

数值模拟在粉末冶金中的应用概况

简介数值模拟应用在粉末冶金中的一些基本模型和方法以及近来在粉末压制、注射成形。

国内钛粉应用现状

粉末冶金技术是降低钛及钛合金工件成本的有效途径,将促进未来钛粉市场向低成本、高品质方向发展。特别是3D打印市场的不断扩大,将推动高品质钛粉不断向前发展。鉴于钛粉产业发展潜力,通过对钛粉在国内的生产、销售、出口、进口等情况和钛粉在航天航空、石油化工、海洋工程和生物医疗等领域的应用情况以及粉末冶金对钛粉质量的要求等进行了分析和总结,认为未来钛粉在航空航天、海洋工程、生物医疗等领域的应用潜力巨大。钛粉将向低成本、高品质方向发展;钛粉末成型将向大型化、精密化、个性化发展。

粉末高温合金的研究现状

粉末高温合金由于其在高温下展现出一系列的优异性能而引起了广泛关注。概述了国内外粉末高温合金的发展历程,同时分析了粉末高温合金的最新研究进展,并展望了该合金未来的发展趋势。

锰在粉末冶金材料中的应用

概述锰(或其化合物)在烧结钢、铜熔渗剂、阻尼合金、铝合金、钛铝合金、钨基重合金、硬质合金等材料中的应用情况,指出这些材料中使用锰的目的以及锰对材料性能的影响。可以预期,在提高粉末冶金材料的性能与粉末冶金新材料的开发中,锰将发挥重要作用。