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首页> 外文学位 >Fabrication, thermal expansion, thermal conductivity, and mechanical properties of high particulate volume fraction aluminum-matrix composites.
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Fabrication, thermal expansion, thermal conductivity, and mechanical properties of high particulate volume fraction aluminum-matrix composites.

机译：高颗粒体积分数铝基复合材料的制造，热膨胀，导热性和机械性能。

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摘要

High particulate volume fraction (up to 75 vol.%) aluminum-matrix composites are technologically important in electronic packaging as thermal conductors of low thermal expansion {dollar}(10times10sp{lcub}-6{rcub} spcirc{dollar}C{dollar}sp{lcub}-1{rcub}){dollar} and low density. The particles used included AlN, SiC and Al{dollar}sb2{dollar}O{dollar}sb3.{dollar} The use of AlN as the reinforcement resulted in superior high temperature (up to 600{dollar}spcirc{dollar}C) resistance and higher shear strength than the use of SiC, due to the reactivity between SiC and Al. The Al/Al{dollar}sb2{dollar}O{dollar}sb3{dollar} exhibited the lowest mechanical properties due to particle clustering in preform and incomplete infiltration in composite. The SiC-Al reaction may be diminished by using a silicon-containing Al matrix, but such a matrix is inherently brittle compared to pure Al, thus resulting in low tensile strength and low ductility in the composite.; The composites were fabricated by infiltration of liquid aluminum into a porous reinforcement preform. The SiC-Al reaction produced Si, which diffused toward the excess liquid metal around the preform, thus causing a relatively low Si concentration at the edge of the composite next to the excess aluminum. However, the non-uniform Si distribution did not result in a non-uniform mechanical property variation. In the case that a mold-Al reaction (as for a steel mold) occurred in addition to the SiC-Al reaction, a non-uniform mechanical property variation resulted.; The quality of the composites depended on the preform fabrication technology, which is more critical in high particulate volume (than in lower whisker/fiber) fraction preform fabrication due to much lower porosity and pore size for liquid metal infiltration. In this work, this technology which involved the use of binder and carrier, binder/carrier ratio, binder-reinforcement reactivity, and optimal preform baking, was developed for high volume fraction particulate preforms. The technology developed used an acid phosphate binder (with P/Al molar ratio = 23) in the amount of 0.1 wt.% of the preform, in contrast to the much larger binder amount used for whisker preforms. The preforms were made by filtration of a slurry consisting of the reinforcement particles, the binder and a carrier (preferably acetone), and subsequent baking (preferably at 200{dollar}spcirc{dollar}C) for the purpose of drying. Baking in air at 500{dollar}spcirc{dollar}C instead of 200{dollar}spcirc{dollar}C caused the AlN preforms to oxidise, thereby decreasing the thermal conductivity of the resulting Al/AlN composites. The reinforcement-binder reactivity was larger for AlN than SiC, but this reactivity did not affect the composite properties due to the small binder amount used.
机译：高颗粒体积分数（最高为75 vol。％）的铝基复合材料在电子包装中作为低热膨胀系数的热导体{dollar}（10×10sp {lcub} -6 {rcub} spcirc {dollar} C {dollar} sp {lcub} -1 {rcub}）{美元}和低密度。所使用的颗粒包括AlN，SiC和Al {dollar} sb2 {dollar} O {dollar} sb3。{dollar}。使用AlN作为增强材料可产生较高的高温（最高600 {sp} {dol} C）。由于SiC和Al之间的反应性，因此比使用SiC具有更高的抗腐蚀性和更高的剪切强度。 Al / Al {sal} sb2 {o} s {sb3} o3的机械性能最低，这归因于预成型坯中的颗粒团聚和复合材料中不完全的渗透。通过使用含硅的Al基体可以减少SiC-Al反应，但是这种基体与纯Al相比固有地是脆性的，因此导致复合材料的低拉伸强度和低延展性。通过将液态铝渗透到多孔增强型预成型件中来制造复合材料。 SiC-Al反应产生的Si扩散到预成型坯周围的多余液态金属中，因此在复合材料的边缘（靠近多余的铝）处引起相对较低的Si浓度。但是，不均匀的Si分布不会导致不均匀的机械性能变化。在除了SiC-Al反应之外还发生铸模-Al反应（对于钢模）的情况下，导致机械性能的不均匀变化。复合材料的质量取决于预成型件的制造技术，这对于高颗粒体积（比较低晶须/纤维）级的预成型件制造更为关键，因为液体金属渗透的孔隙率和孔径要低得多。在这项工作中，该技术涉及到粘合剂和载体的使用，粘合剂/载体的比例，粘合剂增强的反应性以及最佳的预成型坯烘烤，从而用于高体积分数的颗粒预成型坯。所开发的技术使用的酸式磷酸盐粘合剂（P / Al摩尔比= 23）的量为预成型坯的0.1 wt。％，而晶须预成型坯的粘合剂用量大得多。通过过滤由增强颗粒，粘合剂和载体（优选丙酮）组成的浆料，并随后进行烘烤（优选在200spC）进行干燥来制备预成型坯。在空气中在500 {C而不是200spC的温度下烘烤会导致AlN预成型件氧化，从而降低所得Al / AlN复合材料的导热系数。 AlN的增强粘合剂反应性比SiC大，但由于使用的粘合剂量少，该反应性不会影响复合材料的性能。

著录项

  • 作者

    Lai, Shy-Wen.;

  • 作者单位

    State University of New York at Buffalo.;

  • 授予单位 State University of New York at Buffalo.;
  • 学科 Engineering Materials Science.; Engineering Mechanical.; Engineering Metallurgy.; Engineering Packaging.
  • 学位 Ph.D.
  • 年度 1993
  • 页码 284 p.
  • 总页数 284
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;机械、仪表工业;冶金工业;包装工程;
  • 关键词

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