钨—钼梯度功能材料的显微结构

自从梯度功能材料(FGM)的概念提出以后,全世界范围内对这种先进材料各种不同的应用做了大量的研究工作。FGM也能应用到动态高压技术中。震动技术为高压和高拉伸速率下材料性能的试验特征提供了特殊的能力。最近,已有关于梯度密度层材料在高压技术中应用的报道。但在报道中只是将一系列的薄板结合来制备梯度密度材料,如钽、铜、钛、铝、镁和TPX-塑料,因此层结构材料的密度在厚度方向上增加幅度很大。如果利用具有连续或半连续密度变化的材料将可能产生良好的效果。日本学者R. Tu等人报道了梯度材料Al-Cu系FGM的制备,这种具有中等…     

机械工程用功能梯度材料涂层制备技术及其应用

介绍了国内外功能梯度材料 (FGM )的应用现状和发展方向 ,分析比较了目前功能梯度材料的主要制备方法和分类。列举了现阶段FGM材料的应用范围。在此基础上提出了对我国发展应用FGM材料的一些构思和需要注意的问题     

ZrO2／NiFGM中微观残余热应力分析

陶瓷—金属FGM成分沿厚度方向变化，微观残余热应力分析对确定FGM材料体系极为重要。按球对称模型采用弹性理论进行分析，确定了微观残余热应力与陶瓷和金属相的弹性性能、在FGM中的位置的关系。结果表明，微观应力具有短程分布特点，并且在同一梯度层内最大微观应力处于相界面处。同时，通过对ZrO2／Ni FGM制备过程中的陶瓷—金属界面应力的分析表明，FGM制备过程中可能在基体中产生大量微裂纹。     

生物功能梯度材料的制备技术及性能评价

应用于生物领域的一类功能梯度材料统称为生物功能梯度材料(FGM)。生物功能梯度材料具有其独特的结构机理、优良的性能及潜在的应用价值。本文介绍了生物功能梯度材料的简单分类,并且从制备技术及性能评价等方面对生物功能梯度材料进行了总结。     

梯度功能材料研究的一些进展

综述了近年来梯度功能材料(FGM)在优化设计、制备、性能评价以及应用方面的最新研究进展，并对其中的热点问题作了系统阐述。对于热应力缓和型FGM，其优化设计的关键环节是准确分析残余热应力的大小和分布。液相法制备FGM以其低成本、操作简单的优势将会获得更大的发展。对FGM的性能测试要尽可能模拟实际使用环境下载荷的不均匀分布。梯度功能热障涂层是FGM的重要应用之一，它与传统的热障涂层相比可明显提高耐久性。此外，还介绍了FGM在面向等离子体护墙材料以及生物材料上的应用。     

高熔点金属系梯度功能材料

复合材料在高温下使用时有热应力集中和热变形问题，作为解决这些问题的手段，开发了不仅材料成分连续变化就连包括微孔在内的组织也连续变化，不形成特异界面层而将不同功能融合成一体的不均质材料，这就是所谓的梯度功能材料（FGM）．作为高熔点金属系梯度功能材料，包括金属一金属系和金属一陶瓷系两大类．金属一金属系FGM：作为典型的材料开发了不互相固溶的W／Cll系FGM，能耐高热负荷的钨与导热性高的适合强制冷却的钢设计成梯度变化的W／Cll系构造，可采用烧结浸沙法（一种粉末冶金法）制造．它是将气孔率连续变化的钨烧结体加…     

PSZ/Mo功能梯度材料的有限元设计

利用有限元分析的方法,依据拉应力和比应力最小原则对PSZ/Mo功能梯度材料进行了优化设计,确定了FGM的最佳形状分布因子、层数和每一层的厚度.并对最优成分分布FGM在稳态隔热状态下所产生的温度场和热应力进行了计算,得出进行PSZ/Mo功能梯度材料优化设计所需考虑的主要因素.     

功能梯度材料的制备与应用

阐述了功能梯度材料的概念,介绍了功能梯度材料的各种制备工艺技术,最后探讨了FGM在航空航天、机械、能源、光电、生物、电磁和核工程等领域的广泛应用.     

W/ODS铁素体钢功能梯度材料热应力分析

目的 研究W/ODS铁素体钢功能梯度材料（W/ODS FGM）服役条件下的热应力,期望获得较合理的W/ODS FGM材料设计,以达到热应力优化的效果。方法 采用有限元分析方法,结合偏滤器的服役条件,通过改变W/ODS FGM材料梯度层成分分布指数p、梯度层厚度HFGM以及金属W涂层厚度HW,探索各参量的变化对热应力大小及分布的影响。结果 梯度层成分分布指数p值增大,梯度层的应力值会随之增大,而W层的热应力先减小后增大。当p=0.5时,最大热应力出现在梯度层的中段;当p=1、2时,最大应力由FGM层中段转移至FGM/W层的交界处。梯度层厚度HFGM增大,涂层的热应力会大幅提高。梯度层厚度较厚或较薄都会导致热应力在FGM/W交界处集中。W涂层厚度HW增大,会导致W/FGM界面的热应力增大,增添了涂层自身的不稳定性。结论 梯度层成分分布指数和厚度的增大均会引起涂层热应力的增大,并导致最大热应力区的转移。W涂层的增厚会使结构的热应力增大,且最大应力值位于W/FGM界面,不利于涂层寿命的提高。HW=HODS=1 mm、HFGM=8 mm、p=0.5和HW=HODS=1 mm、HFGM=4 mm、p=1的最大热应力区位于梯度层中段,且后者的最大应力值小于前者,故HW=HODS=1 mm、HFGM=4 mm、p=1的结构较优。     

HA/316L粉非对称生物FGM的微观组织与增韧机制

采用热压工艺制备了HA／316L粉非对称生物功能梯度材料（FGM）。HA／316L粉非对称生物FGM在宏观上呈现明显的梯度,微观上则表现出成分连续变化,且各成分分布均匀、弥散。在各梯度层内部及界面都没有裂纹及大孔洞出现,界面结合紧密。随着316L粉的含量增加,韧窝的数量逐渐增加,韧窝形貌由浅变深,边缘由尖锐逐渐变得圆滑,表明材料由脆性断裂向韧性断裂转化。纯HA梯度层为典型的脆性断裂,HA80／316L和HA60／316L梯度层表现为典型的晶间断裂,HA40／316L和HA20／316L梯度层断裂性质为晶间断裂中掺杂有韧性断裂,而316L梯度层则表现为典型的韧性断裂。316L粉的加入改变了HA／316L粉生物FGM各梯度层的断裂方式,从而提高了材料的力学性能。从整体上而言,HA／316L粉生物FGM主要增韧机制包括层间裂纹偏转增韧与裂纹偏转增韧。     

Preparation of Ti-Mo system functionally graded materials by co-sedimentation

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钛基梯度功能材料的复合结构研究进展

介绍了钛基梯度功能材料复合结构的概念和开发背景，回顾了近些年来在钛基梯度功能材料宏细观尺度研究方面所取得的研究成果，并对钛基梯度功能材料复合结构的发展趋势作一展望。由于这种材料中，各组分材料的体积含量在空间位置上是连续变化的，其物理性能没有突变，因而可较好地避免诸如在纤维增强复合材料中经常出现的层间应力问题或降低应力集中现象。梯度功能材料目前已被发展用来作高温环境下的结构用件，本文着重论述了钛基梯度功能材料复合结构在材料优化分析领域的研究现状及其应用前景，并提出需要进一步研究的方向。     

TiB2-Cu-Ni梯度功能材料的抗烧蚀行为

采用燃烧合成与同时致密化技术制备了TiB2-Cu-Ni5层金属-陶瓷梯度功能材料。利用扫描电镜(SEM)、电子探针(EPMA)等方法对梯度材料的成分及烧蚀前后的微观组织形貌等进行了检测，用等离子火炬电弧加热器对材料进行加热来考察梯度材料的抗热震性能以及抗烧蚀性能。结果表明，梯度功能材料各层之间的界线已经模糊，层与层之间的结合较好；梯度材料在瞬间加热时和瞬间冷却时均未出现崩裂，烧蚀后表面没有裂纹产生，说明该梯度材料具有优异的抗热震性能；烧蚀20S后，梯度功能材料烧蚀后的质量损失仅为0．5g，说明梯度功能材料具有良好的抗烧蚀性能。梯度材料的抗烧蚀机理为金属粘接剂的挥发损失、热化学烧蚀和机械冲刷。该梯度材料在固体火箭发动机的喷管、喉衬等部件上有广阔的应用前景。     

Preparation of Al/Si functionally graded materials using ultrasonic separation method

Functionally graded materials （FGM） have been widely used in many industries such as aerospace, energy and electronics. In this experimental study of fabricating FGM, an approach was developed to prepare AI/Si FGM using power ultrasonic separation method. Material sample with continuously changing composition and performance/properties was successfully produced. Results showed that the microstructure of the FGM sample transited, from its top to bottom, from the hypereutectic structure with a large quantity of primary Si gradually to the eutectic, and finally to the hypoeutectic with numerous primary AI dendrites. The distribution of primary Si and microhardness of the FGM sample also presented graded characteristics, resulting that the wear resistance of the FGM sample decreased from top to bottom. Preliminary discussion was made on the mechanism of the formation of AI/Si FGM.     

Plasma spray forming of functionally graded materials mould

A new technology of functionally graded materials(FGM) mould fabricated by plasma spraying and arc spraying was developed. According to applied characteristic of plastic mould, the reasonable coatings of FGM were designed and their microstructures were analyzed. At the same time, some key problems were solved including spray mould fabricating, FGM forming and demoulding, etc. The results show that the service performance of the FGM mould is much more excellent than the one composed of the traditional materials, and the life span can also be greatly increased. The technology will have a significant influence on materials development in mould industry.     

羟基磷灰石／钛生物功能梯度材料种植体与骨的结合强度

采用动物兔活体植入与剪切强度试验考察r羟基磷灰石(HA)／Ti生物功能梯度材料(FGM)种植体与头骨基体的结合强度。结果表明，HA—Ti FGM种植体／骨结合强度随植入时间延长迅速增高，其强度值与纯HA植入体相当而大大优于纯Ti种植体；植入3个月时，HA—Ti FGM与周围骨组织的结合强度可达6．49MPa。剪切断口形貌表明，FGM种植体断裂发生在界面的新骨一侧，说明其界面结合强度甚至超过了新生骨组织本身的剪切强度。     

W/Cu功能梯度材料的制备及应用

W/Cu功能梯度材料性能优异应用广泛,以W/Cu功能梯度材料的制备方法为研究对象,探讨不同制备方法存在的优缺点,包括熔渗法、粉末冶金法及等离子喷涂法。作为等离子体材料应与等离子体相适应,耐热冲蚀。在电子领域中,其一侧应满足与基板的封接问题,另一侧满足高导热、低热膨胀系数的要求。目前虽然研发出多种新工艺、新技术,但需进一步了解其控制因素及影响机理,另外每种工艺适用范围比较小,需开发高效、低成本、适用广、易控制的制造工艺。     

Functionally gradient (YSZ-20% Al<Subscript>2</Subscript>O<Subscript>3</Subscript>)−SUS422 composites

Functionally gradient materials (FGMs) were prepared by mixing 5 layers comprised of different ratios of (YSZ-20%Al₂O₃) and 422 stainless (SUS422) powders, followed by hot pressing for densification. Two design concepts were proposed: One as a FGM with a monotonic change of the CTE (coefficient of thermal expansion) for each layer, and is designated as the monotonic mode, and the other was a FGM with a change of CTE that is not monotonic for each layer, and is termed the non-monotonic mode. The FGM with a monotonic CTE mode cracked at the ceramic surface after it was removed from the hot pressing furnace. In contrast, the FGM with a non-monotonic CTE mode survived after hot pressing. Based on ABAQUS simulation results, a non-monotonic change in CTE resulted in a decrease of residual stress on the ceramic side but an increase inside the metal-rich layers of the FGMs. The induced change in the stress distribution inside the FGMs was compromised by the deformation of the metal-rich ingredient (SUS422) in the FGM. Thermal shock tests of FGMs were performed between 25°C and 600°C. The non-monotonic FGM endured up to 100 thermal cycles with only slight bending, and was free of delamination and cracking. The use of composition-adjusted layers to manipulate thermal expansion coefficients of each layer greatly changed the stress contour of the FGM. It is noted that a modified functional-gradient FGM can be fabricated with a hard ceramic surface on one side to resist high temperature, and a ductile metallic surface on the other side to provide toughness.     

MICROSTRUCTURE AND THERMAL STRESS RELAXATION OF ZrO_2－Ni FUNCTIONALLY GRADED MATERIAL

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Effect of varied alumina/zirconia content on ballistic performance of a functionally graded material

Functionally graded materials (FGMs) are characterized by continuous variation in their composition and structure with thickness or volume. Hence, the corresponding changes in the properties and functions of the FGMs can be investigated to create new materials. In this study, four-layered FGM specimens with three different compositions, i.e., Al₂O₃/(0, 5, 10, 15%) ZrO₂, Al₂O₃/(0, 10, 20, 30%) ZrO₂ and Al₂O₃/(0, 15, 30, 45%) ZrO₂, were designed. The ceramic specimens were hexagons whose sides were 11 mm long. Accordingly, 6061-T6 Al was used as a back plate. A ballistic test was conducted using 0.3″ armor-piercing bullets with an initial speed of 868 ± 15 m/s. Numerical simulation software, i.e., LS-DYNA, was employed to analyze stress transfer and the fracture of the FGM specimens under impact. The ballistic test showed that the Al₂O₃/(0, 5, 10, 15%) ZrO₂ FGM exhibited the best impact resistance performance. The investigation of microstructures through observation using a SEM did not show delamination in the FGM interlayer after impact. Furthermore, the abrasion between the ceramic and projectile increased. XRD analysis verified the phase transformation of ZrO₂ from the tetragonal phase to the monoclinic phase. This transition delayed crack growth and increased material toughness, thereby promoting the impact resistance performance of the FGMs.