喷射成形快速凝固技术在铝合金中的应用

喷射成形作为一种新兴的快速凝固技术，已经被广泛地应用于研制和开发各种高性能的快速凝固材料，近年来发展非常迅速。叙述了喷射成形有技术在高强铝合金系，高比强、高比模量Ａｌ－Ｌｉ合金系，耐热高强Ａｌ－Ｆｅ合金系列及铝工复合材料等方向的研究概况及应用；着重讨论该技术对不同系列铝合金的组织和性能的影响。     

粉末冶金铝合金

本文概述了粉末冶金铝合金的发展现状和前景。较详细地介绍了普通粉末冶金铝合金和高性能粉末冶金铝合金的组成、制备工艺、性能和应用。     

高性能航空铝合金结构材料的动态研究

随着航空工业的发展,对航空铝合金材料性能的性能提出了更高的要求,本文分析研究了高性能航空铝合金结构材料的动态和发展趋势。调整合金的化学成分、降低杂质元素含量、改进材料制备、加工和热处理工艺是提高航空铝合金性能的主要手段,而发展超高强铝合金、高强高韧铝合金、低密高强高刚Al-Li合金、高强耐热铝合金、高强超塑性性铝合金和铝基复合材料等是发展航空铝合金结构材料的主要目标。     

高强铝合金剥落腐蚀的研究综述

文章对高强铝合金剥落腐蚀机理、影响剥落腐蚀的主要因素以及防腐对高强铝合金剥落腐蚀的研究现状及前沿问题进行了综述,展望了高强铝合金剥蚀与防腐研究的发展趋势。     

深圳市鑫美达粉末冶金有限公司

深圳市鑫美达粉末冶金有限公司简介： 深圳市鑫美达粉末冶金有限公司于1998年成立并投产，是一家专业生产粉末冶金零部件的公司，主要产品有：1．高精度粉末冶金含油轴承：2．高强庭磺攀冶金齿轮、结构零件及异型零件：3．粉末冶金不锈钢制品．[第一段]     

浅谈中国铝及铝合金材料产业现状与发展战略(2)

3．2变形铝及铝合金材料的研发 目前全世界已正式注册的铝合金达千种以上，最常用的有442种，分别包括在1XXX到9XXX系中，为世界经济的发展和人类文明的进步做出了巨大贡献。但是，随着科技的进步，国民经济和国防军工的现代化发展及人民生产水平的提高，有些合金已被淘汰，急需发展一批高强、高韧、高模、耐磨、耐蚀、耐疲劳、耐高温、耐低温、耐辐射、防火、防爆、易切割、易抛光、可表面处理、可焊接的和超轻的新型合金。如6b≥750MPa的高强高韧合金，密度小于2．4的铝锂合金，粉末冶金和复合材料等。     

粉末冶金生物医用Ti合金的研究及应用现状

Ti及Ti合金具有低密度、高比强度、较低的弹性模量以及优异的耐腐蚀性能和生物相容性,因而成为生物医用材料的首选。本文简要介绍了粉末冶金技术制备Ti及其合金的主要特点及其优势,从粉末准备、成形、烧结、性能4个方面综述了粉末冶金医用Ti合金的研究进展,并总结了目前粉末冶金医用Ti合金的应用状况;针对目前存在的主要问题,分析了粉末冶金医用Ti合金的发展方向及其应用前景。     

高强铝合金第二相强化及其机理

在较系统地介绍高强铝合金显微组织与性能关系的基础上,重点讨论了高强铝合金中第二相的类型、来源、主要显微特征、作用及强韧化机理.     

铝粉末冶金制品的应用将获得发展

一个由德国教育和研究部资助的来自Fraunhofer研究院、GKN烧结金属公司、Ecka公司和ZF公司的跨行业专家小组的调查表明:铝粉末冶金制品在汽车制造领域中应用的前景光明,铝粉末冶金制品的应用可以减少汽车的重量,降低燃油消耗和废气的排放。现在多数结构铝粉末冶金制品的成分是锻造或铸造合金的成分,多数是以2000或6000铝合金为基本成分,含铜、镁和硅,已有一些可用于生产精密铝粉末冶金制品的合金粉被开发出来了。近期铝粉末冶金开发的一个方向是近、过共晶成分的Al-Si合金,这种成分的铝合金具有良好的力学性能和抗磨损能力。铝粉末冶金…     

Al-Zn-Mg-Cu系超强铝合金的研究现状与展望

Al-Zn-Mg-Cu系超强铝合金因为高强度和高韧性,已作为轻质高强结构材料广泛应用于航空航天领域.该文主要介绍国内外高强铝合金的发展历程及最新研究进展, 指出Al-Zn-Mg-Cu超强铝合金的研究经历了高强低韧→高强耐蚀→高强高韧耐蚀→超强高韧耐蚀4个发展阶段,认为调控晶界结构及晶界析出相状态已成为目前铝合金研究的重点;简要评述微观组织和晶界结构对超强铝合金性能的影响,并介绍超强铝合会弥散相和形变-热处理工艺的研究现状及其调控晶界结构和晶界析出相状态的原理.最后指出寻找新型弥散相和开发新型的形变-热处理工艺足提高超强铝合金性能的重要发展方向和途径.     

High strength aluminium alloys prepared by nanocrystallisation of amorphous powders using spark plasma sintering

Al based nanocrystalline alloys with high fracture strength are fabricated using consolidation and controlled crystallisation strategy of amorphous powder precursors. The sintered product exhibits high specific strength of 3.18?×?10⁵?Nm?kg^??1. The compacted microstructure and ultrafine grains caused by sufficient densification and crystallisation of Al based amorphous powders are responsible for considerable properties of the sample. Furthermore, the densification process and mechanical behaviour of the sintered Al based nanocrystalline alloy are investigated in detail. The Al based nanocrystalline alloys prepared by synergetic process of powder consolidation and crystallisation of amorphous can exhibit much improved mechanical properties compared with conventional Al alloys, which can have potential engineering applications.     

Solid state sintering and consolidation of Al powders and Al matrix composites

As an attempt to depart from conventional transient liquid phase sintering practice, solid state vacuum sintering was studied in loose powder and in hot quasi-isostatically forged samples composed of commercial inert gas atomized (CIGA) or high purity Al powder. The high purity Al powder was generated by a gas atomization reaction synthesis (GARS) technique that results in spherical powder with a far thinner surface oxide. After vacuum sintering at 525 °C for up to 100 h, SEM results showed that the GARS Al powder achieved significantly advanced sintering stages, compared to the CIGA Al powder. Tensile results from the forged samples also showed that although its ultimate tensile strength is lower, 95 vs. 147 MPa, the ductility of the GARS pure Al sample is higher than the CIGA Al sample. Forging also consolidated a model powder-based composite system composed of an Al matrix reinforced with quasi-crystalline Al–Cu–Fe powders, where the same powder synthesis methods were compared. Auger surface analysis detected evidence of increased matrix/reinforcement interfacial bonding in the composite sample made from GARS powder by alloy interdiffusion layer measurements, consistent with earlier tensile property measurements. The overall results indicated the significant potential of using Al powders produced with a thin, high purity surface oxide for simplifying current Al powder consolidation processing methods.     

Mechanical properties and fracture behavior of an ultrafine-grained Al-20 wt pct Si alloy

The effect of powder particle size on the microstructure, mechanical properties, and fracture behavior of Al-20 wt pct Si alloy powders was studied in both the gas-atomized and extruded conditions. The microstructure of the as-atomized powders consisted of fine Si particles and that of the extruded bars showed a homogeneous distribution of fine eutectic Si and primary Si particles embedded in the Al matrix. The grain size of fcc-Al varied from 150 to 600 nm and the size of the eutectic Si and primary Si was about 100 to 200 nm in the extruded bars. The room-temperature tensile strength of the alloy with a powder size <26 μm was 322 MPa, while for the coarser powder (45 to 106 μm), it was 230 MPa. The tensile strength of the extruded bar from the fine powder (<26 μm) was also higher than that of the Al-20 wt pct Si-3 wt pet Fe (powder size: 60 to 120 μm) alloys. With decreasing powder size from 45 to 106 μm to <26 μm, the specific wear of all the alloys decreased significantly at all sliding speeds due to the higher strength achieved by ultrafine-grained constituent phases. The thickness of the deformed layer of the alloy from the coarse powder (10 μm at 3.5 m/s) was larger on the worm surface in comparison to the bars from the fine powders (5 μm at 3.5 m/s), attributed to the lower strength of the bars with coarse powders.     

Development and properties of aluminium silicon alloy fly ash composites

Abstract

Aluminium (Al) silicon alloy fly ash composites were developed using powder metallurgy technique. Aluminium silicon alloy powder was homogenously mixed with various weight percentages of fly ash (5–15%) and uniaxially cold pressed at pressures ranging between 200 and 515 MPa, and the green specimens were sintered at temperatures between 575 and 625°C. The various properties of the Al alloy fly ash composites were studied and compared with that of base alloy. The density of Al alloy fly ash composites was lower than that of the base alloy. The sintered density of the Al alloy fly ash composites and Al alloy slightly decreased when compared to green density. The hardness of the Al alloy fly ash composites was higher than that of base alloy and it increased with the increase in weight percentage of fly ash content upto 12 wt-%. Compressive strength of the composites was lower than that of base alloy and it decreased with increasing weight percentage of fly ash. The electrical resistivity and corrosion rate of the composites were higher than that of base alloy and they increased with increasing weight percentage of fly ash. Scanning electron microscope was used to examine the microstructural characteristics of the composites. X-ray diffraction pattern was used to identify various phases present in Al alloy fly ash composites.     

Mechanical properties and fracture behavior of an ultrafine-grained Al-20 wt pct Si alloy

The effect of powder particle size on the microstructure, mechanical properties, and fracture behavior of Al-20 wt pct Si alloy powders was studied in both the gas-atomized and extruded conditions. The microstructure of the as-atomized powders consisted of fine Si particles and that of the extruded bars showed a homogeneous distribution of fine eutectic Si and primary Si particles embedded in the Al matrix. The grain size of fcc-Al varied from 150 to 600 nm and the size of the eutectic Si and primary Si was about 100 to 200 nm in the extruded bars. The room-temperature tensile strength of the alloy with a powder size <26 μm was 322 MPa, while for the coarser powder (45 to 106 μm), it was 230 MPa. The tensile strength of the extruded bar from the fine powder (<26 μm) was also higher than that of the Al-20 wt pct Si-3 wt pct Fe (powder size: 60 to 120 μm) alloys. With decreasing powder size from 45 to 106 μm to <26 μm, the specific wear of all the alloys decreased significantly at all sliding speeds due to the higher strength achieved by ultrafine-grained constituent phases. The thickness of the deformed layer of the alloy from the coarse powder (10 μm at 3.5 m/s) was larger on the worn surface in comparison to the bars from the fine powders (5 μm at 3.5 m/s), attributed to the lower strength of the bars with coarse powders.     

微波烧结YG12硬质合金脱碳的控制

通过在混合料中增加炭黑和在填料中添加炭黑两种方法,来抑制微波烧结YG12硬质合金在微波烧结过程中出现的脱碳现象,从而提高微波烧结硬质合金的性能.结果表明:在混合料中添加炭黑可以抑制合金的脱碳行为,当炭黑添加量为0.4％(质量分数)时,合金的抗弯强度较理想,合金抗弯强度可达2 250 MPa;而通过在填料中添加炭黑有效抑...     

钛与钛合金的低成本清洁制备新技术

提出了多级深度热还原的理念,发明了镁热/铝热自蔓延-深度多级还原制备钛与钛合金的关键技术,成功制备出纯度为99.69%高纯还原钛粉,Ti6Al4V合金粉：Ti:89.5-90.2%、Al:5.85-6.57%、V:3.90-4.17%,氧含量<0.15%;制备出20kg级规模的TiAl合金铸锭,Ti/Al原子比为1:1,氧含量为0.09%。成果已在山东傅山集团成功转化应用,500t/a还原钛粉工业示范线于2018年12月08日试车成功,可使金属钛与钛合金的生产成本降低30%以上,项目的推广应用为钛材低成本清洁利用奠定工业化基础。     

以机械合金化新工艺制造弥散强化铝镁合金

把纯铝粉和铝-镁合金粉与炭黑或有机试剂（如甲醇、硬脂酸等）在高能球磨机内研磨,获得机械合金化粉末。将这种粉末冷等静压密实,然后在820°K下挤压,挤压比为26:1,最后制得合金棒材。这种棒材的机械性能检验结果表明,用机械合金化新工艺制造的弥散强化铝-镁合金,机械性能优良。例如54号合金,其机械性能是,σ_b519—529MN/m2,σ_0.2510—519MN/m2,δ4—6%,Ψ9-14%。实验结果还表明,采用这种新工艺制造的铝-镁合金,与铸造铝-镁合金相比,它的机械性能有很大的改善和提高。特别是在573°K温度下经100小时退火后,其极限抗张强度下降得很小或完全不下降。因此这类合金作为一种结构材料使用将会有很大的潜力。     

快凝AlCrYZr合金挤压成形与组织性能

添加Y合金化、配制AlCrYZr合金,采用金相、X射线衍射、透射电镜、扫描电镜、力学拉伸实验等研究手段,研究了快速凝固AlCrYZr合金粉末挤压成形工艺以及其对组织性能的影响。结果表明,实验合金中主要第二相为Al₂₀Cr₂Y(立方,a=1.44nm)和Al₃Zr;挤压成形时提高挤压比,降低挤压温度,有利于改善粉体结合状况,得到Ll₂Al₃Zr质点,同时细化Al₂₀Cr₂Y质点,使合金获得动态回复组织,从而使合金具有良好的低温、高温强度和塑性。     

Effect of distribution of B4C on the mechanical behaviour of Al-6061/B4C composite

In this work, the effect of mixing parameters on the distribution of B₄C in 6061-Al alloy and its correlation with mechanical behaviour was studied. 6061-Al alloy powder was mixed with 10 mass-% B₄C powder in a ball mill and powder rotator mixer by varying mixing time from 1 to 5?h. Mixing was performed in both wet and dry conditions in a ball mill while only dry condition was used in the powder rotator mixer. The green compacts were sintered at 630°C. The quadrat method was used to quantify the distribution of B₄C particles in the microstructures of sintered Al/B₄C composite. The results showed that the distribution was improved with mixing time but the density, hardness and compression strength of Al/B₄C composites were reduced with time during ball milling. On the other hand, the distribution of reinforcement, density, hardness and compressive strength of Al/B₄C composites was improved with mixing time in the powder rotator mixer.