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本文建立了TiBw/Cu、(TiB2p+TiBw)/Cu、TiB2p /Cu复合材料的三维细观结构有限元模型,基于ABAQUS非耦合的热电分析理论,通过有限元数值模拟方法揭示了复合材料微观结构特征参量与宏观导电性能之间的定量关系。结果表明:TiB2颗粒体积分数为导电率主要影响因素,随体积分数增大导电率逐步减小,颗粒粒径大小对导电率影响不显著;TiB晶须体积分数和晶须取向角为导电率主要影响因素,晶须取向角平行于电流方向时导电率最好,垂直于电流方向时的导电率最差。在颗粒晶须混杂增强复合材料中,增强体体积分数和晶须取向角为导电率的主要影响因素,增强体种类对导电率影响较小。本文为颗粒晶须混杂增强铜基复合材料导电率计算提供了新的思路和方法,对颗粒和晶须增强复合材料混杂设计提供依据。 相似文献
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新一代Al-Ti-C晶粒细化剂的工业应用 总被引:13,自引:3,他引:10
最近的研究证明,AlTiC晶粒细化剂不存在与AlTiB中TiB2有关的缺点,TiC聚集倾向小和对锆、铬中毒免疫.介绍了研制的新型AlTiC晶粒细化剂的实验室试验和工业应用试验结果.对99.7%Al的实验室试验表明AlTiC的晶粒细化效果比进口AlTiB的好.在纯铝铸轧板的初步试用中也获得了良好的结果,在A356合金中已获得了工业应用. 相似文献
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陶瓷颗粒增强Mg65Cu20Zn5Y10块体金属玻璃复合材料 总被引:6,自引:0,他引:6
在块体玻璃形成合金Mg65Cu20Zn5Y10中添加10%(体积分数)的SiC或15%的TiB2陶瓷颗粒,经铜模浇铸形成块体金属玻璃复合材料.这些第二相颗粒的引入对基体合金的玻璃形成能力未产生明显的不良影响.陶瓷第二相颗粒弥散分布于金属玻璃基体上.复合材料的轴向压缩断裂强度达到1GPa,为Mg65Cu20Zn5Y10块体金属玻璃的1.2倍.Mg65Cu20Zn5Y10块体金属玻璃的断裂发生于弹性形变阶段,断裂前几乎观察不到塑性形变.与之相对照,含有TiB2颗粒的复合材料断裂前可表现出约0.9%的塑性应变. 相似文献
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1 INTRODUCTIONBoroncarbidehasmanyoutstandingproperties ,suchasextremelyhighhardness (385 0kg·mm- 2 ,loweronlytodiamondandcubicboronnitride) ,ex cellentstabilitytowardtheeffectofvariousacids ,highmeltingpoint (2 4 5 0℃ ) ,highvalueofelasticmodulus (4 5 0GPa)andlowdensity(2 .5 2 g·cm- 3) .Allthesepropertiesallowboroncarbidetocoverawiderangeoftechnologicalapplicationsincludingcut tingtools ,wearresistantcomponentsandlightarmormaterials[14 ] .However ,owingtothestrongcovalentbondsinitslat… 相似文献
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In situ A356/TiB2 composites were successfully fabricated via in-melt reaction among aluminium alloy, K2TiF6 and KBF4 compounds. The composite was examined by using XRD, SEM and EDX techniques. The experimental results reveal that TiB2 are dispersed homogeneously into the aluminium alloy matrix. The mechanical properties of the composites increase significantly with the addition of reinforcement, and the tensile fractography of the composite exhibits to be ductile though the elongation of the composites decreases compared with the unreinforced matrix alloy. 相似文献
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烧结方式对TiB2/Cu复合材料组织和性能的影响 总被引:1,自引:0,他引:1
采用微波烧结和真空烧结制备了Cu及不同TiB2含量的TiB2/Cu复合材料。测试了试样的密度、硬度、电导率,并对不同烧结法方式制备的Cu及TiB2/Cu复合材料的组织和性能进行了分析。结果表明,微波烧结技术可以在较短的时间和较低的能耗下完成烧结,且烧结体的性能要明显优于真空烧结的。但微波烧结试样的组织比较粗大,有孪晶存在,并且孪晶数量随TiB2含量的增加而减少。 相似文献
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采用TiB2颗粒与铝粉混配的方法,获得利于成形的预制体,采用压力浸渗法制备体积分数为20%的TiB2P/6061Al复合材料,并采用10:1的挤压比对复合材料进行热挤压。利用扫描电镜(SEM)、透射电镜(TEM)和万能电子拉伸机对热挤压前后复合材料的微观组织及力学性能进行研究,发现经过该种方法制备的复合材料经热挤压后具有良好的室温拉伸力学性能,抗拉强度为447.5MPa,弹性模量为121.8GPa,延伸率可达7.95%,显示出良好的强塑性配合,分析其强塑性来源于增强体与基体之间的良好界面结合、晶粒细化强化和沉淀强化。 相似文献
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D. Galvan V. Ocelík Y. Pei B. J. Kooi Jeff Th. M. De Hosson E. Ramous 《Journal of Materials Engineering and Performance》2004,13(4):406-412
TiB/Ti-6Al-4V metal-matrix composite (MMC) layers were produced on Ti-6Al-4V substrates by laser cladding. A TiB2/Ti powder mixture was used as a precursor to obtain a dispersion of TiB needles in the Ti alloy matrix, with the aid of an
exothermic reaction between TiB2 and Ti. A eutectic microstructure was obtained that consisted of an extremely homogeneous dispersion of TiB eutectic needles
in the Ti alloy matrix, having a volume fraction as high as 0.33. Also, an equilibrium-like microstructure was found, consisting
of a dispersion of both primary and eutectic TiB needles inside the Ti alloy matrix. An analysis of the geometry of the layers
was performed and proved successful in determining the percentage of B. Further, it correctly predicted the variation of atomic
B content as a function of laser power. The relative wear resistance coefficient, defined as the wear coefficient of the uncoated
matrix divided by that of coating, shows an improvement by a factor as high as 1500 for the eutectic microstructure.
This paper was presented at the 2nd International Surface Engineering Congress sponsored by ASM International, on September
15–17, 2003, in Indianapolis, Indiana, and appeared on pp. 411–18 of the Proceedings. 相似文献
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利用ProCAST软件对A356合金半固态压铸件下壳体进行耦合数值模拟。结果表明,在模具温度为220℃,充型温度为590℃、压射速度为5m/s时,半固态浆料充型平稳,温度场分布均匀,减少了缩孔、缩松等缺陷,为A356合金半固态压铸成形工艺的制定和优化提供了依据。采用此工艺参数,生产出合格铸件。在该件上所需部位可以钻螺纹孔,与其他零件装配使用。通过试验,验证了数值模拟优化工艺参数的合理性。 相似文献
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运用铸造过程数值模拟软件ProCAST,对转子铸件进行了浇注温度的模拟仿真分析,以研究不同浇注温度对QT400-15转子铸件缺陷的影响。结果显示:温度过高虽然可以提高流动性,但是同时会增加液体在凝固过程中的收缩量,导致缩孔缩松缺陷;而温度过低,又会导致铸件力学性能达不到要求。根据试验情况,浇注温度宜选在1 340~1 360℃。 相似文献
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In the present study, the densification of Ti/TiB composites, the growth behavior ofin-situ formed TiB reinforcement, the effects of processing variables — such as reactant powder (TiB2, B4C), sintering temperature and time — on the microstructures and the mechanical properties ofin-situ processed Ti/TiB composites have been investigated. Mixtures of TiB2 or B4C powder with pure titanium powder were compacted and presintered at 700°C for 1 hr followed by sintering at 900, 1000, 1100,
1200, and 1300°C, respectively, for 3hrs. Some specimens were sintered at 1000°C for various times in order to study the formation
behavior of TiB reinforcementin-situ formed within the pure Ti matrix. TiB reinforcements were formed through different mechanisms, such as the formation of fine
TiB and the formation of coarse TiB by Ostwald ripening or the coalescence of fine TiB. There was no crystallographic relationship
between TiB reinforcement and the matrix. There were voids at the interface between the TiB reinforcement and the Ti matrix
due to the preferential growth of coarse TiB without a particular crystallographic relationship with pure Ti matrix and the
surface energy between the Ti matrix and TiB reinforcements. Therefore, the densification of Ti/TiB2 compacts was hindered by the preferential growth of coarse TiB reinforcements. The mechanical properties ofin-situ processed composites were evaluated by measuring the compressive yield strength at ambient and high temperatures. The compressive
yield strength of thein situ processed composites was higher than that of the Ti-6A1-4V alloy. It was also found that the compressive yield strength of
the composite made from TiB2 reactant powder was higher than that of the composite made from B4C at the same volume fraction of reinforcement. A crack path examination suggested that the bonding nature of interface between
matrix and reinforcement made from TiB2 reactant powder was better than that made from B4C. 相似文献
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铝合金连铸工艺参数的辅助优化 总被引:2,自引:1,他引:2
采用有限差分方法,自行开发了连铸过程的凝固温度场模拟软件。通过调整工艺参数,对A356铝合金圆柱坯垂直连铸过程温度场进行了模拟,利用固一液界面形状及位置参数确定了合适的工艺参数。根据该工艺参数进行了相应的连铸试验,并将实测时间.温度历程曲线和固,液界面形状及位置分别与模拟结果进行了对比。结果表明,可以利用该软件对铝合金连铸工艺参数进行辅助优化。 相似文献
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采用挤压铸造法制备了不同体积分数的TiBzv/6061Al复合材料,利用扫描电镜、透射电镜、硬度计、三点弯曲等手段对复合材料的组织与力学性能进行了研究,分析了热处理工艺对其组织性能的影响。结果表明:不同的热处理条件下TiB2P/6061Al复合材料的组织不同:退火态时观察到再结晶晶粒和少量位错:时效态时观察到大量的位错和析出相,界面产物尺寸比退火态时相对大些,且在界面附近的基体中存在明显的无析出区。热处理状态对弹性模量的影响不大,但对材料的硬度和抗弯强度影响较大。45%TiB2v/6061Al复合材料时效处理后硬度和抗弯强度分别比退火态时提高了40%和23%。 相似文献
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应用化学镀铜方法对TiB2颗粒进行表面镀铜,采用微波烧结技术制备了含TiB2体积分数不同的TiB2/Cu复合材料,测试了试样在50~300℃区间的膨胀系数,探讨了TiB2含量及其表面改性对TiB2/Cu复合材料热膨胀系数的影响。结果表明:随着TiB2含量的增加,复合材料的膨胀系数降低;TiB2颗粒表面镀铜后,在TiB2相同含量条件下,TiB2/Cu复合材料的膨胀系数进一步降低;理论模型计算结果表明,TiB2未镀铜的TiB2/Cu复合材料的膨胀系数与ROM模型计算值相符合,而TiB2镀铜的TiB2/Cu复合材料的膨胀系数与Kerner模型计算值相符合,反映了TiB2颗粒镀铜后能很好地改善颗粒与基体的结合。 相似文献