共查询到20条相似文献,搜索用时 46 毫秒
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为研究纳米颗粒增强铝基复合材料的高温蠕变特性,基于6063Al-Al2(SO4)3体系,采用超声化学原位合成技术,制备出不同Al2O3体积分数(5%、7%)的纳米Al2O3/6063Al复合材料,通过高温蠕变拉伸试验测试其高温蠕变性能,利用XRD、OM、SEM及TEM分析其微观形貌。结果表明:施加高能超声可显著细化增强体颗粒并提高其分布的均匀性,所生成的Al2O3增强颗粒以圆形或近六边形为主,尺寸为20~100nm;纳米Al2O3/6063Al复合材料的名义应力指数、表观激活能和门槛应力值与基体相比大幅提高,均随着增强体体积分数的增加而提高,表明纳米Al2O3/6063Al复合材料的抗蠕变性能提高;纳米Al2O3/6063Al复合材料的真应力指数为8,说明复合材料蠕变机制符合微结构不变模型,即受基体晶格扩散的控制;纳米Al2O3/6063Al复合材料的高温蠕变断口特征以脆性断裂为主,高应力下形成穿晶断裂,低应力下形成沿晶断裂和晶界孔洞;纳米Al2O3/6063Al复合材料的主要强化机制为位错强化与弥散强化。 相似文献
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固溶处理对GH4169G合金蠕变的影响 总被引:1,自引:0,他引:1
研究了固溶处理温度对GH4169G合金晶粒组织、晶界析出和蠕变的影响。结果表明,随着固溶处理温度的提高(由980℃提高到1020℃)GH4169G合金的晶粒尺寸明显增大,晶界d相的尺寸和数量明显减少,晶内g″相的析出变化不大;合金的650℃/700 MPa稳态蠕变速率明显降低,表观蠕变激活能明显增大,蠕变断裂寿命显著延长。固溶处理温度对680℃/725 MPa的蠕变性能有相同的影响趋势,但其程度减弱。孪晶的形成是GH4169G合金的重要蠕变机制。提高固溶处理温度使晶界d相的析出减少,晶界滑动蠕变速率降低;同时使晶粒度增大,形成孪晶的阻力增大,晶粒蠕变速率降低。 相似文献
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研究了应力、温度和热处理对22vol%莫来石短纤维增强LY12复合材料性能的影响,实验采用铸态、退火态和T4处理复合材料,三种状态下复合材料的抗蠕变性能均高于基体材料LY12铝合金.文中提出一种复合材料的蠕变机制:在低应力阶段,复合材料的蠕变受位错的攀移过程所控制;在高应力阶段,复合材料的蠕变受增强体与基体的界面所控制.用TEM分析了材料的界面. 相似文献
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综合国内外的研究成果,论述了P92钢在高温蠕变过程中不同的析出相对P92钢性能的影响。结果表明M23C6相在高温蠕变过程中粗化较快,会失去对P92钢马氏体晶界的钉扎强化作用;Laves相形成初期能够提高P92钢的蠕变断裂强度,但是当Laves相到一定尺寸后会降低P92钢的蠕变断裂强度;Z相的析出不但增加了蠕变孔洞出现的几率,而且会减少基体中的MX相,降低MX相的弥散强化作用,所以Z相的析出对P92钢高温蠕变性能有不良影响。同时论述了可以采用形变热处理生产工艺和控制合金元素含量等措施强化P92钢的高温蠕变性能。 相似文献
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目的 研究2219铝合金搅拌摩擦焊接头的蠕变变形行为、力学性能及其微观组织演变规律,探明焊接态铝合金材料的蠕变变形与强化机制,为超大型高筋薄壁构件板坯搅拌摩擦拼焊+蠕变时效形性一体化制造提供理论与技术支撑。方法 通过蠕变时效实验和室温性能测试,研究了有焊缝和无焊缝材料的蠕变时效行为与力学性能演变,结合应力指数、激活能计算和透射电镜表征,分析了焊缝对2219铝合金蠕变时效特性的影响。结果 与母材相比,有焊缝铝合金整体蠕变量更低,但前期短时蠕变速率高而后期长时变形速率低,变形机制由母材的扩散蠕变转为位错攀移;有焊缝材料蠕变时效后抗拉强度增加量相对更少,屈服强度增加量基本相同,表现为加工硬化能力降低。同时,焊核区晶粒细小、晶内析出大量弥散的GPⅡ区、θʹʹ和θʹ相,且晶界附近出现无沉淀析出带,热影响区和热机影响区析出相长大,但热机影响区析出相开始出现粗化。结论 在蠕变时效过程中,搅拌摩擦焊后的2219铝合金复杂的微观组织演变会提高材料的蠕变变形和强度提升敏感性,上述发现为优化搅拌摩擦焊与蠕变时效成形工艺参数匹配提供了基础。 相似文献
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相比于金属基和陶瓷基复合材料,聚合物基复合材料的抗蠕变性能较差,这使聚合物基复合材料的应用受到一定的限制。向聚合物中添加适当的填充物是改善其抗蠕变性能的一种行之有效的方法。文中综述了零维、一维及二维纳米尺寸的填充物对热塑性和热固性聚合物蠕变性能影响的研究进展,并对纳米填充物增强聚合物抗蠕变性的机制进行了分析。详细分析和比较了碳纳米管对环氧树脂蠕变性能影响的研究进展,总结了目前研究的热点和难点,并对未来研究的方向进行了展望。 相似文献
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N. G. Chernorukov N. V. Karyakin E. V. Suleimanov S. V. Barch M. I. Alimzhanov 《Radiochemistry》2002,44(3):216-218
The enthalpies of formation of Al(PUO6)2(OH)·11H2O and Al(AsUO6)2(OH)·13H2O at 298.15 K were determined. The isobaric heat capacities were measured in the range 80-300 K. The absolute entropies, entropies, and Gibbs functions of formation of these compounds under standard conditions were evaluated. 相似文献
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梁蓓 《中国材料科技与设备》2008,5(2):22-23
利用电解铝液直接配料生产铝及铝合金铸锭是当前国内外盛行的一种生产技术。本文介绍了它的生产意义、熔炼和保温技术、铝熔体的处理技术,铸造工艺技术及其生产流程图。希望引起铸造工作者的注意,并进一步研究开发。 相似文献
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铝材重量轻,比强度高、易成型,具有优良的导电、导热性能,在建筑、交通、机械、通讯、化工仪器仪表、航天航空、家电、日用品等国民经济的各个领域都获得了广泛的应用。生产中要用卤化物对其表面进行处理,当介质中含有Cl-等活性阴离子时,铝表面钝化膜的溶解和修复... 相似文献
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铝合金具有密度小、强度高、导电导热性好及加工简单等优点,基于这些综合性能的优势,其作为结构和散热材料广泛应用于汽车、电子及通讯等领域.然而随着系统及设备向着集成化、小型化、轻量化及高功率等方向发展,以铝为主体的金属材料的散热面临着严峻挑战.本文综述了国内外高导热铝合金及铝基复合材料的研究与开发现状,阐述了铝合金的导热机理以及合金成分和加工工艺等对铝合金导热性能的影响规律,分析了高硅铝、铝-碳化硅、铝-金刚石、铝-石墨片/碳纳米管等系列铝基复合材料的导热特性,展望了高导热铝合金及铝基复合材料研究存在的问题及未来的发展方向. 相似文献
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V. M. Kevorkijan 《Materials and Manufacturing Processes》1999,14(4):509-524
In this work, the potential of Finely powdered aluminum dross by-product (d50 = 67 (μm) as a cost effective reinforcement in discontinuously reinforced aluminum matrix composites (A356) was investigated on the basis of quality-cost modeling. Using a standard rheocasting procedure, samples of composite material were obtained consisting of 20 vol.% of as-received and laboratory processed grades of dross particles which differed mainly in particle size and level of impurities.
Inspection of the tensile properties of these different composite materials showed that a slight improvement in strength over the unreinforced matrix is achievable only by the introduction of fine dross particles with an average particle size less than 10 μm. In composites with larger dross particles the strengthening effect was not observed. In contrast, evaluation of the wear properties demonstrated that the introduction of coarse and as-received dross particles in an aluminum matrix results in a significant improvement in the wear resistance of the composite material. However, in that case, there is a sacrifice in strength. Quality-cost modeling of these two grades of dross reinforced aluminum based composites indicates that both may be applicable for some less critical engineered and wear resistant components, with possible widespread application in the transportation industry. 相似文献
Inspection of the tensile properties of these different composite materials showed that a slight improvement in strength over the unreinforced matrix is achievable only by the introduction of fine dross particles with an average particle size less than 10 μm. In composites with larger dross particles the strengthening effect was not observed. In contrast, evaluation of the wear properties demonstrated that the introduction of coarse and as-received dross particles in an aluminum matrix results in a significant improvement in the wear resistance of the composite material. However, in that case, there is a sacrifice in strength. Quality-cost modeling of these two grades of dross reinforced aluminum based composites indicates that both may be applicable for some less critical engineered and wear resistant components, with possible widespread application in the transportation industry. 相似文献
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本文论述了铝合金阳极氧化二重封闭工艺及封闭膜层的性能,并对二重封闭膜层比重铬酸钾膜层抗蚀能力有明显提高进行了分析。 相似文献
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铝及铝合金零件镀银前化学浸锌的工艺研究 总被引:2,自引:0,他引:2
对铝及铝合金电镀工艺的难点进行了分析,通过化学浸锌前处理工艺的试验研究,确定了二次浸锌的较优工艺配方及条件为:400~500 g/L NaOH,50~80 g/L ZnO,适量添加剂,室温,第一次浸锌0.5~1.0 min,第二次浸锌0.5~1.0 min.通过外观、结合力、耐蚀性、电器焊接性能测试表明,经该工艺处理后能获得性能优良的银镀层,满足了生产需求. 相似文献
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Aluminum Coatings for Steel 总被引:3,自引:0,他引:3
Aruna Bahadur 《Materials and Manufacturing Processes》1996,11(2):225-232
Aluminum coated steel possesses excellent oxidation and corrosion resistance in sulfur and marine: environments and can substitute for expensive alloy of steels. Hot dip aluminizing (HAD) and pack cementation calorizing (CAL) are dealt with in detail. IN HDA coats, some alloying action takes place, when the substrate is dipped in molten Al at 973 K for 1-2 minutes. The coat consists of an outer pure Al layer, followed by a hard intermetallic layer consisting of FeAl3 and Fe2Al5, forming a serrated interface with the base. Isothermal holding of such samples at 773-933 K for 10 minutes leads to further diffusion and phase changes. This improves resistance to thermal shock and bending. In CAL coats, the process parameters (1173-1223 K/2-4 h and pack composition), were optimized, resulting in appreciable alloying. The surface layer consists of Fe3Al and FeAl, which is comparable to the inner alloy layer of HDA coats. The structures/ property correlation is carried out for both coatings and the results compared. 相似文献