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Discontinuously reinforced copper-matrix composites by powder metallurgy.

机译：粉末冶金法不连续增强的铜基复合材料。

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摘要

High reinforcement volume fraction is important for discontinuously reinforced copper-matrix composites to obtain sufficient strengthening and low coefficient of thermal expansion (CTE), which are required for electronic packaging, electrical contacts, motor brushes and electrodes. The maximum reinforcement volume fraction depends on the composite fabrication method and the reinforcement morphology. In this dissertation, copper-matrix and brass-matrix composites were made by powder metallurgy (P/M). The reinforcements included molybdenum particles, silicon carbide whiskers and titanium diboride platelets. The method used was the coated filler method, in which a reinforcement coated with the matrix metal was used. In contrast, conventional P/M uses the admixture method, which involves a mixture of matrix powder and reinforcement. For all the composite systems, the coated filler method was found to be superior to the admixture method in providing composites with lower porosity, greater hardness, higher compressive yield strength, greater abrasion resistance, greater scratch resistance, lower CTE, higher thermal conductivity and lower electrical resistivity, though the degree of superiority was greater for solid-phase P/M (for copper) than transient liquid-phase P/M (for brass), and was greater for high than low reinforcement contents. In the coated filler method, the coating on the reinforcement separated reinforcement units from one another and provided a cleaner interface and stronger bond between reinforcement and matrix than what the admixture method could provide.; The highest reinforcement content attained in dense composites ({dollar}<{dollar}5% porosity) made by the coated filler method was 70 vol.% Mo, 54 vol.% SiC and 60 vol.% TiB{dollar}sb2{dollar}, compared to the values of 60 vol.% Mo, 33 vol.% SiC and 50 vol.% TiB{dollar}sb2{dollar} for composites made by the admixture method. In particular, the SiC whisker content of 54 vol.% is much greater than the previously attained maximum of 40 vol.%, thus resulting in exceptional hardness (260 Brinell).; Among Cu/Mo, Cu/TiB{dollar}sb2{dollar} and Cu/SiCw at the same reinforcement volume fraction (50%), Cu/Mo gave the lowest CTE, highest thermal conductivity and lowest electrical resistivity, while Cu/SiCw gave the greatest hardness and Cu/TiB{dollar}sb2{dollar} and Cu/SiCw gave the highest compressive yield strength. Compared to Cu/SiCw, Cu/TiB{dollar}sb2{dollar} exhibited much higher thermal conductivity and much lower electrical resistivity.
机译：高的增强体积分数对于不连续增强的铜基复合材料以获得足够的增强和低的热膨胀系数（CTE）很重要，这是电子封装，电触点，电动机电刷和电极所需的。最大的钢筋体积分数取决于复合材料的制造方法和钢筋的形态。本文采用粉末冶金法制备了铜基和黄铜基复合材料。增强材料包括钼颗粒，碳化硅晶须和二硼化钛薄片。所使用的方法是涂覆填料方法，其中使用涂覆有基质金属的增强材料。相反，常规的P / M使用混合方法，该方法涉及基质粉末和增强材料的混合物。对于所有复合材料系统，发现涂层填料方法在提供更低孔隙率，更高硬度，更高抗压屈服强度，更高耐磨性，更高耐刮擦性，更低CTE，更高导热率和更低导热率的复合材料方面优于混合法。电阻率，尽管固相P / M（对于铜）的优势程度大于瞬态液相P / M（对于黄铜）的优势程度，对于高含量的增强剂却比低含量的增强剂强。在涂覆的填料方法中，增强材料上的涂层使增强单元彼此分离，并提供了比混合方法所能提供的界面更清洁的界面，增强材料与基体之间的结合更牢固。通过涂覆填料方法制得的致密复合材料（{孔隙度<{dollar} 5％孔隙率）中，最高的补强含量为70 vol。％Mo，54 vol。％SiC和60 vol。％TiB {dollar} sb2 {dollar }，相比之下，采用混合法制得的复合材料的Mo含量为60％（体积），SiC含量为33％（体积）和TiB {dollarssb2 {dollar}（％）}。尤其是，碳化硅晶须含量为54％（体积）远远大于以前达到的最大值（40％（体积）），因此具有出众的硬度（260布氏硬度）。在相同的增强体积分数（50％）下，Cu / Mo，Cu / TiB {美元} sb2 {美元}和Cu / SiCw中，Cu / Mo的CTE最低，导热率最高，电阻率最低，而Cu / SiCw给出最大的硬度，而Cu / TiB {sb2 {s}}和Cu / SiCw给出最高的压缩屈服强度。与Cu / SiCw相比，Cu / TiB {美元} sb2 {美元}表现出更高的热导率和更低的电阻率。

著录项

  • 作者

    Yih, Pay.;

  • 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 Metallurgy.; Engineering Electronics and Electrical.; Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 1996
  • 页码 254 p.
  • 总页数 254
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 冶金工业;无线电电子学、电信技术;工程材料学;
  • 关键词

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