金属基复合材料的力学行为及失效方式(上)

金属基复合材料的研究和应用正在迅速发展,其力学性能和断裂失效方式以及相应的检测手段都与传统材料有很大差别。本文系统地介绍了金属基复合材料的强度、弹性模量、断裂韧性、疲劳强度等各种力学行为的性能特点及相适应的检测方法。此外还介绍了他们的高温性能、物理性能特点。对短纤维和颗粒增强的金属基复合材料和长纤维增强的金属基复合材料的失效方式分别进行了论述。分析了他们与传统材料的差别。最后并对金属基复合材料的力学行为研究的发展趋势提出了看法。     

短纤维增强金属基复合材料的弹性模量和屈服强度

基于文献[ 1 ]提出的变形模型和获得的应力分析结果, 推导出了短纤维增强金属基复合材料弹性模量和屈服强度理论表达式。表达式预测的结果与实验结果吻合很好, 并与Eshelby 模型及有限元数值模型预测结果表现出很好的一致。分析表明, 复合材料的弹性模量和屈服强度相对于基体材料弹性模量和屈服强度的增加主要来自应力传递的贡献。      

单向复合材料弹塑性变形行为的研究

本文利用微观力学方法研究了单向连续纤维增强的金属基复合材料的弹塑性变形行为。纤维是线弹性材料,基体是弹性一粘塑性各向同性材料。在复合材料的纵向拉伸、横向拉伸和纵向剪切变形状态下,预测了复合材料的弹性模量和初始屈服应力值,并考虑了应变率对弹塑性变形行为的影响。以硼/铝复合材料为例,进行了数值分析,预测结果与实验值符合较好。      

液态金属铸造法制备金属基复合材料的研究现状

在金属基复合材料的制备方法中,液态铸造法具有广泛的应用和发展前景.较系统地论述了颗粒、晶须和短纤维增强的金属基复合材料的液态铸造制备方法及其对材料性能的影响,探讨了液态铸造法制备金属基复合材料过程中仍然存在的问题和研究进展,展望了制备金属基复合材料的发展方向.     

混杂增强金属基复合材料的研究进展

传统金属基复合材料在强度和弹性模量提高的同时,塑韧性急剧下降,因此很大程度上限制了它的应用范围。为了满足高技术领域的需求,改善复合材料的塑韧性,利用多相同时增强金属基复合材料的"混杂效应",在不同尺度、不同层次上进行结构设计和优化,发挥各种增强相的优势。混杂增强体之间的相互作用、混杂效应等使得复合材料具备更低的热膨胀系数、更高的耐磨性和更优越的力学性能等,同时还降低原料的成本。这都使得它成为航空、航天和国防尖端技术领域最富有研究潜力的战略性材料,并将带动整个工业技术的进步。介绍了混杂增强金属基复合材料结构种类及其研究进展,综述了各种构型设计的基本原理及其优缺点;展望了混杂增强金属基复合材料构型及功能化的发展方向及工程化需要解决的关键问题。     

金属基复合材料的发展现状及展望

介绍了金属基复合材料的发展现状,重点介绍了几种制备金属基复合材料的方法,提出了一种新的制备方法块体分散法,并指出了在制备技术中存在的主要问题及其对应问题的解决方法,最后展望了金属基复合材料的发展趋势.     

金属基复合材料产业化及标准现状

本文总结了国内外金属基复合材料的应用领域及产品应用现状,对现有金属基复合材料标准、规范进行了分析、比较,提出了我国金属基复合材料标准体系框架设想,指出建立我国金属基复合材料标准体系搭建的必要性,以期尽早形成与我国科研、生产相匹配的金属基复合材料标准体系.     

非连续增强金属基复合材料剧烈塑性变形行为研究进展

综述了非连续增强金属基复合材料剧烈塑性变形(SPD)行为的研究进展,系统阐述了等径弯曲通道变形(ECAP)、高压扭转(HPT)、多向锻造(MF)、累积叠轧(ARB)和循环挤压压缩(CEC)5种SPD的加工原理和方法。集中介绍了这些方法在铝基、镁基、铜基和钛基等金属基复合材料方面应用的研究进展。重点介绍了金属基复合材料SPD的微观组织演化和变形力学行为,详细阐明了金属基复合材料SPD机制以及超细晶形成机理,指出了金属基复合材料在SPD中存在的深层次问题及发展趋势,展望了利用SPD方法制备超细晶非连续增强金属基复合材料的应用前景。     

金属基混杂复合材料的研究进展

本文综述了金属基混杂复合材料的研究进展。着重介绍了各种金属基混杂复合材料的发展背景、组成、工艺方法和性能特点,并对其发展前景作了分析,认为纤维与颗粒混杂增强的金属基复合材料和树脂基复合材料与铝合金的超混杂复合材料是最具活力的品种。     

金属基复合材料多尺度计算方法研究进展

多尺度计算方法是系统深入研究金属基复合材料宏微观力学性能联系的重要计算方法。重点分析并总结了常用的两种金属基复合材料多尺度计算方法,即解析计算方法和有限元计算方法,论述了两种方法各自的优缺点。并详细说明各种多尺度计算方法的适用范围和优缺点,指出金属基复合材料多尺度计算方法的发展趋势。     

Review on TiC reinforced steel composites

Particulate reinforced ferrous-based metal matrix composites exhibit both excellent wear and cutting properties, and can give significant cost reductions over existing materials used in heavy wear applications. This paper reviews the current status of literature on titanium carbide–reinforced steel matrix composites and looks into the different types and methods of reinforcements being used, together with other alternative processing routes. Mechanical properties such as elastic modulus, low and high temperature strengths and wear properties are discussed as a function of the volume fraction of reinforcement. The review concludes by underlining the importance of further research in some critical areas to fully realize the industrial potential of these composites.     

The modeling and determination of dynamic elastic modulus of magnesium based metal matrix composites

The aim of the present study was to determine elastic modulus of the magnesium-based composites containing different volume fraction of SiC particulates using an innovative free-free beam type impact based technique. This technique is based on classical vibration theory, by which the geometry and material properties of the metal matrix composites are related to resonant frequency of the test specimen. With the fundamental resonant frequency obtained from the experiment and density determined by the Archimedes' principle, the elastic modulus values were determined. In addition, a finite element model is proposed for different SiC weight percentage samples for the determination of dynamic elastic modulus using the first natural frequency corresponding to the flexural mode. The elastic modulus values obtained using finite element method were found to be in close agreement with the values obtained from the impact based experiments and in better agreement when compared to theoretical methods such as Halpin-Tsai method. Both the theoretical approaches, in common, exhibit the increasing trend of elastic modulus value with an increase in weight percentage of SiC particulates.     

Modelling and determination of dynamic elastic modulus of magnesium based metal matrix composites

Abstract

The aim of the present study was to determine the elastic modulus of magnesium based composites containing different volume fractions of SiC particulate using an innovative suspended beam type impact based technique. This applies classical vibration theory, which relates the resonant frequency of the test specimens to the geometry and material properties of the metal matrix composites. The elastic modulus values were determined from the funda mental resonant frequency obtained from the experiment and density measurements. In addition, a finite element model was proposed for determining the dynamic elastic modulus of MMCs with different SiC reinforcement content using the first natural frequency corresponding to the flexural mode. The elastic modulus values obtained from the finite element model were in close agreement with the values obtained from the impact based experiments and in better agreement than those from theoretical methods such as the shear lag, Eshelby, and Halpin–Tsai models.     

电化学方法制备金属基复合材料研究进展

金属基复合材料具有高比强度、高比模量、高硬度、耐高温等一系列优点,在现代航空、航天及武器装备等领域具有广阔的应用前景.综述了近年来电化学方法制备金属基复合材料的研究进展,具体介绍了电化学渗浸、连续分步电沉积和复合电沉积3种不同的电化学工艺过程.     

原位自生Ti3 Al金属间化合物基复合材料的微观结构

采用原位自生（XD）法制备Ti3Al金属间化合物基复合材料,对复合材料的XRD,OM和SEM的分析结果表明,Ti-17Al-0.5C复合材料的基体为Ti3Al,增强相为Ti3AlC,且增强相在基体中按一定的方位排列,Ti-17Al-1.5(2.0)C复合材料的基体为Ti3Al,增强相由心部TiC矣包覆层Ti3AlC双层组成,随着含C量的增加,增强相由不发达的树脂晶变为等轴晶,对合金进行微力学探针测试表明,增强相TiC和Ti3AlC的显微硬度和弹性模量均大于基体Ti3Al,随着C含量的增加,合金中增强相和基体的显微硬度和弹性模量无明显变化。     

碳纳米管增强金属基复合材料的研究进展

碳纳米管增强金属基复合材料由于高的比强度、比模量以及优异的热、电性能在航空航天领域具有很好的应用潜力,本文在分析大量文献的基础上,评述该类材料的制备技术和界面研究进展,对其典型性能进行归纳,指出碳纳米管的分散技术以及碳管、基体之间的界面特性应该是今后本领域的重点研究方向。     

C/C复合材料液相浸渍制备工艺及其力学性能模拟

针对酚醛先驱体C/C复合材料液相浸渍制备工艺各组分相的化学转化特性, 基于Arrhenius方程建立了C/C复合材料液相浸渍制备工艺力学模型, 详细分析了固化-炭化和石墨化两个重要的工艺阶段各组分相的体积变化规律, 得到的气孔体积分数与Micro-CT系统扫描处理的细编穿刺C/C复合材料微结构图像中气孔体积分数相吻合, 并结合均匀化方法对制备过程材料基体有效弹性模量进行了预测。结果表明: 材料基体的有效弹性模量随着致密化次数的增加而增大, 在每一次致密化过程中材料基体的有效弹性模量先增大后减小, 石墨化工艺过程中材料基体的有效弹性模量达到某一值后保持平稳。      

Investigation of the Young''s modulus of TiB needles in situ produced in titanium matrix composite

In situ Ti/TiB composites with different volume fractions of discontinuous TiB reinforcements were produced by powder metallurgy. After compacting Ti+TiB₂ powders by hot unidirectional pressure, heat treatments led to the in situ formation of distinctive needles of TiB, randomly distributed in the titanium matrix. The Young's modulus of TiB was evaluated using the ASW computation method and experimental Vickers micro-indentation. Three point bend tests were performed on Ti/TiB composites as a function of the TiB volume fraction in order to extract the Young's modulus of TiB from the elastic properties of the composite. The different values obtained according to these three methods were discussed and compared with the literature.     

On the mechanical behavior of aluminum alloys reinforced by long or short alumina fibers or SiC whiskers

This study was initiated to examine the dispersion of longitudinal and transverse waves in metal matrix composites in order to obtain the dynamic elastic modulus and to evaluate various models for predicting the composite's macroscopic elastic constants from the properties of its constituents. The materials chosen for this investigation were alumina continuous fibers on the one hand and alumina and SiC short fibers on the other hand, all embedded in an aluminum alloy matrix. In addition, some indications have been obtained experimentally for the acoustoelastic effect in the composite.     

Dissimilar Friction Stir Welding Between 5083 and 6082 Al Alloys Reinforced With TiC Nanoparticles

Dissimilar friction stir welding between aluminum alloys thick plates reinforced with TiC nanoparticles was conducted. The defect-free welds are characterized by good mechanical mixing between the joined materials as well as by good nanoparticle distribution and further grain refinement in comparison with the unreinforced weld. The local mechanical behavior of the produced metal matrix composites was studied and compared with their bulk counterparts and parent materials. Specifically, the measured mechanical properties in microscale and nanoscale (namely hardness and elastic modulus) are correlated with microstructure and the presence of fillers. The hardness, elastic modulus, ultimate tensile strength, percentage of elongation, and yield values increase with the presence of TiC nanoparticles.