共查询到19条相似文献,搜索用时 140 毫秒
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采用SHS/QP工艺制备了(TiB2+Fe)/Fe叠层材料。SEM分析表明TiB2+Fe金属陶瓷层结构致密。用EPMA研究了TiB2+Fe金属陶瓷层与Fe基片之间的界面连接机制,结果表明TiB2从TiB2+Fe侧向Fe基片侧进行扩散,以及TiB2+Fe层中的Fe粘结相和Fe基片的粘接完成了(TiB2+Fe)/Fe叠层材料的界面连接。叠层材料接头断裂时,断裂位置发生在TiB2+Fe金属陶瓷层,而不是沿着TiB2+Fe层与Fe基片的界面断裂。 相似文献
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以Al熔液为载体,采用原位反应生成形状规则、尺寸细小的TiB2颗粒相,再将TiB2颗粒传递到ZA27合金中,形成TiB2颗粒增强的ZA27复合材料。采用合理的熔炼工艺促进了TiB2颗粒在基体中的均匀分布。实验结果显示,TiB2颗粒在ZA27复合材料中,分布均匀,平均直径在3 μm以下。TiB2颗粒的加入使得复合材料的晶粒明显细化,并随着TiB2颗粒含量增加,复合材料的抗拉强度、硬度明显提高,2.1%TiB2/ZA27复合材料与基体合金相比室温抗拉强度提高13%、布氏硬度提高21%,弹性模量也有所提高,在强度、硬度及弹性模量提高的同时,材料的塑性并未恶化,延伸率略有提高,另外,材料的热膨胀系数随着TiB2颗粒的加入有所降低。 相似文献
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采用化学共沉淀法合成前驱体,经1150℃ 烧结3.5 h得到近零膨胀26 wt% ZrW2O8/ZrO2复合陶瓷,并利用X射线衍射仪、扫描电镜和热膨胀仪研究了原料中加入Al(NO3)3·9H2O对26 wt% ZrW2O8/ZrO2复合陶瓷的相组成、致密度和热膨胀性能的影响。研究结果表明,少量添加Al(NO3)3·9H2O可有效提高复合材料致密度,所得复合陶瓷的组分仍为立方结构的α-ZrW2O8和单斜的m-ZrO2,其中添加2.21 wt% Al(NO3)3·9H2O的复合材料的致密度达到理论密度的98.67%,且对复合陶瓷的热膨胀性能影响不大。其促进致密化机制为晶界处低熔点液相物质Al2(WO4)3提高了复合材料的烧结性能,消除气孔促进致密化。 相似文献
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热分析结果表明,对于B2O3-TiO2-Mg-C体系,可利用SHS还原技术合成出TiB2-TiC陶瓷复合粉。其化学反应机理为:Mg先还原B2O3和TiO2,新生的Ti与B和C反应生成TiB2和TiC; TiO2的还原经历了TiO2→TiO→Ti的逐步过程。采用一定的酸洗工艺得到了纯净的TiB2-TiC陶瓷复合粉。复合粉中包含六方片状TiB2和圆球状TiC;复合粉中1μm以下颗粒质量百分数超过45%,87%以上的颗粒大小在3μm以下。在TiB2-TiC中,TiC<em>y以一种贫碳结构存在,物料中Ti被B或C结合形成TiB2和TiC<em>y,y的值为0.7483。 相似文献
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为探索第三组元Y2O3添加对Al2O3/ZrO2共晶陶瓷显微组织与机械性能的影响,本文利用低温度梯度的高温熔凝法制备了直径为20 mm的Al2O3/ZrO2(Y2O3)共晶陶瓷块体,采用SEM、EDS及XRD技术对共晶陶瓷进行微结构分析,并利用维氏压痕法对其硬度和断裂韧性进行测试。SEM结果表明,凝固组织由群集的共晶团结构组成,随着Y2O3添加量的增加,共晶团形态由胞状转变为枝晶状,内部相间距在1~2 μm范围内变化。力学测试表明,Y2O3摩尔分数小于1.1%时,由于组织内部存在低硬度m-ZrO2及微裂纹缺陷,故陶瓷硬度较低,约为(9.53±0.22 )GPa;当Y2O3摩尔分数为1.1%时,陶瓷硬度最大,约为(18.05±0.27)GPa;当Y2O3的摩尔分数大于1.1%时,由于共晶团边界区内气孔缺陷及粗大组织增多,引起陶瓷硬度值略有下降。低Y2O3摩尔分数添加时,陶瓷断裂韧性相对较高,约为(6.30±0.16)MPa·m1/2,这与其内部存在大量微裂纹缺陷有关;随着Y2O3添加量的增加,陶瓷的微裂纹数量减少、边界区内缺陷增多,断裂韧性降低。 相似文献
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Mo/Ni3Al复合材料的抗氧化性能的研究 总被引:1,自引:0,他引:1
本文研究了Mo/Ni3Al复合材料的抗氧化性能.结果指出,Mo/Ni3Al复合材料在不同温度下的氧化动力学特征服从抛物线规律.随氧化试验温度升高,氧化增重明显增加.MoO2在高温下被氧化成MoO3,对Mo/Ni3Al复合材料的抗氧化性能具有不利的影响. 相似文献
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基于EET理论,计算了F-Zr2(Ni,Cu)和tI-Zr2Cu及tI-Zr2(Cu,Ni)相的价电子结构,用最强键键合力n1、结构单元总成键能力F和单位成键能力Fv分析了F-Zr2Ni亚稳相向tI-Zr2Cu型稳定相的转变过程。研究发现:F-Zr2Ni的nF-Zr2Ni1值比tI-Zr2Cu的ntI-Zr2Cu1值大115.36%,FF-Zr2Niv值比tI-Zr2Cu的FtI-Zr2Cuv值大34.03%;F-Zr2(Ni0.3,Cu0.7)的nF-Zr2(Ni0.3,Cu0.7)1值比tI-Zr2Cu的ntI-Zr2Cu1值大0.36%,FF-Zr2(Ni0.3,Cu0.7)v值比tI-Zr2Cu的FF-Zr2Niv值大1.25%; tI-Zr2(Cu0.6,Ni0.4)的ntI-Zr2(Cu0.6,Ni0.4)1值比F-Zr2(Ni0.3,Cu0.7)的nF-Zr2(Ni0.3,Cu0.7)1值大12.95%, FtI-Zr2(Cu0.6,Ni0.4)v值比F-Zr2(Ni0.3,Cu0.7)的FF-Zr2(Ni0.3,Cu0.7)v值大14.41%; 从价电子结构角度看,F-Zr2Ni不能直接转变为tI-Zr2Cu,F-Zr2(Ni,Cu)不易分解重构为tI-Zr2Cu;F-Zr2(Ni0.3,Cu0.7)可分解并转变为tI-Zr2(Cu0.6,Ni0.4)。 相似文献
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为了研究Ni3Al/TiC之间的润湿性,本工作利用两种Ni3Al,即熔炼方法制备的块体Ni3Al、SHS方法制备的Ni3Al粉末,和致密TiC基板,通过高温摄影显微镜实验测定了Ni3Al-TiC之间的接触角。结果表明:无论哪一种Ni3Al,它们与TiC之间的接触角都在18°以内,表现出与TiC之间的良好的润湿性;当Ni3Al压粉体中掺入少量Mo时,接触角降为11°左右。用XRD、EPMA等方法分析和观察了实验样品的组成、结构、断面形貌及其元素分布。探讨了Mo对改善Ni3Al-TiC润湿性的作用机理。 相似文献
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Reactive infiltration of a NiO-base blended powder with molten aluminium was attempted at 1673 K in order to obtain Al2O3
matrix composites containing a dispersion of Al3Ni, AlNi and/or AlNi3. The NiO powder was barely infiltrated by the molten
aluminium after a 3600 s holding time at 1673 K. A continuous layer of Al2O3 was observed to exist at the infiltration front,
which prevented any further infiltration. TiB2 particles were added to the NiO powder in order to absorb the heat of reaction
between NiO and aluminium. When the TiB2 particle content in the [NiO+TiB2] powder blend was greater than 20 vol%, spontaneous
infiltration occurred completely. Thus, it was shown that the addition of the TiB2 particles assisted in the spontaneous infiltration.
The specimens produced by the in situ reaction consisted of Al2O3, TiB2 and Al3Ni. Al3Ni was mainly located between the TiB2
and Al2O3. The effect of the TiB2 addition on the infiltration kinetics was to decrease the maximum attainable temperature
caused by the exothermic reaction. This in turn prevented the formation of a continuous Al2O3 film at the infiltration front.
This resulted in the production of pathways for the infiltration of the molten aluminium and made possible the complete infiltration.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
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TiB2/Al自润滑复合材料在动压马达零件上的应用研究 总被引:1,自引:0,他引:1
复合材料组织致密,颗粒分布均匀.与基体结合紧密.具有较高的弹性模量和抗弯强度。室温下与GCr15轴承钢对磨时其摩擦系数在0.2左右.自磨时摩擦系数在0.08左右.摩擦表面没有明显的粘着或犁削痕连.磨损率明显低于SiCr/Al复合材料和GT35合金.呈现出较好的自润滑性能。 相似文献
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TiB2P/Al composite was successfully fabricated by squeeze casting technology. Its mechanical and tribological properties were evaluated. The elimination of Ti-Al intermetallic compound was confirmed by X-ray diffraction (XRD) studies. At 45% volume fraction, the bending strength at ambient temperature was 934 MPa. And the fracture modes included ductile failure of Al matrix and brittle fracture of TiB2 particles. In dry sliding wear mode, severe plastic deformation and adhesive wear were found on the worn surfaces of the SiCP/Alcomposite. But no obvious characteristics of adhesion or abrasion wear were observed on that of the TiB2P/Al composites. At the steady stage, the friction coefficient of the SiCP/Al composite was about 0.6. While that of TiB2P/Al composite was only about 0.16~0.17. 相似文献
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提出一种新型的原位反应合成工艺——熔体反应法, 以TiO2、H3BO3、Na3AlF6 和Al-Cu 合金为原材料, 采用熔体反应法制备了低成本的内生颗粒增强Al-4. 5Cu/TiB2 复合材料。TiB2 颗粒细小, 平均尺寸为0. 93 Lm, 均匀分布于基体之中, 与基体结合良好。当TiB2 的含量为10 vo l% 时, 复合材料的抗拉强度为416. 7M Pa, 屈服强度为316.9M Pa, 延伸率为3. 3%。 相似文献
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Al2O3/TiB2/SiCw三元复合材料的力学性能及显微结构 总被引:3,自引:0,他引:3
以Al2O3为基体,SiC晶须和TiB2颗粒两种增韧剂,采用热压烧结工艺制备了Al2O3/TiB2/SiCw三元复合陶瓷材料。研究了热压工艺参数对材料致密度的影响和晶须含量对该复合材料的力学性能和显微结构的影响。结果表明;随晶须含量的增加,该复合材料的热压温度和保温时间需要相应的增加;晶须拔出、裂纹偏转和晶须的桥接为该复合材料的主要增韧机理;随晶须含量的增加,该材料的室温断裂韧性增加;该材料的断裂韧性随温度的升高而呈增大趋势,并且晶须含量越高,材料的高温断裂韧性增幅越大。 相似文献
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A NiAl/TiB2 nanocomposite is synthesized by mechanical alloying elemental powders. Upon milling for a certain time, an abrupt exothermic reaction occurs and a large amount of NiAl and TiB2 compounds form simultaneously. It is suggested that two separate chemical reactions,i.e. Ni+Al →NiAl and Ti+2B→TiB2, are involved during the exothermic reaction. Additionof Ti and B to Ni-Al system impedes the structural evolution of Ni and Al powders and delays the abrupt reaction. The final products are equilibrium phases without any metastable phases formed. This type of reaction is suggested to be suitable for alloy systems with two large heatrelease reactions. 相似文献