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首页> 外文学位 >Reactive pressureless infiltration techniques for Cu-alloy/TiB(2) and other in situ composites: Processing, modeling and analysis.
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Reactive pressureless infiltration techniques for Cu-alloy/TiB(2) and other in situ composites: Processing, modeling and analysis.

机译：铜合金/ TiB（2）和其他原位复合材料的无压反应性渗透技术：加工，建模和分析。

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摘要

Reactive Pressureless Infiltration (RPI) was achieved successfully by the in situ synthesis of Cu-Mn/TiB{dollar}sb2{dollar} composite materials. RPI-processed Cu-Mn/TiB{dollar}sb2{dollar} composite materials with 7 to 40 v/o TiB{dollar}sb2{dollar} exhibit microstructures with fine (0.5-5 {dollar}mu{dollar}m) and evenly dispersed reinforcement and high room temperature strength and hardness. Infiltration occurs spontaneously at relatively low temperatures (980-1050{dollar}spcirc{dollar}C), and does not require complex processing equipment. Primary factors which alter phase composition and microstructure of the MMCs are enthalpy and relative free energy of reinforcement formation, initial powder size, processing temperature and matrix wettability of the reinforcement. Employment of the matrix assisted displacement reaction between the Cu-Ti liquid and MnB{dollar}sb2{dollar}: MnB{dollar}sb2{dollar} + Cu-Ti {dollar}to{dollar} TiB{dollar}sb2{dollar}+ Cu-Mn ensures in situ formation of fine TiB{dollar}sb2{dollar} particulates in the Cu-Mn matrix. The reaction also provides for the spontaneous infiltration of the solid MnB{dollar}sb2{dollar} preform by Cu-Ti liquid due to wettability. The process can be carried out below the melting point of the Cu because alloying Cu with Mn decreases the liquidus temperature of the alloy and causes diffusional melting of the infiltration front. Possible mechanisms for the evolution of the microstructure during processing are proposed and analyzed. The study demonstrates that TiB{dollar}sb2{dollar} is formed by interfacial reaction: Ti + MnB{dollar}sb2{dollar} = TiB{dollar}sb2{dollar} + Mn. A detailed kinetic model of the reactive pressureless infiltration is proposed. The model evaluates the diffusion, infiltration and reaction processes and predicts the infiltration rate, the thickness of the reacted layer as a function of time, the rate of reaction of TiB{dollar}sb2{dollar} formation and the concentration profile of each component in the reactive layer. The model establishes the effects of processing parameters such as reaction time and temperature, wetting of the preform by the melt, preform porosity, preform composition and volume fraction of reinforcement on the infiltration kinetics. It also establishes the limiting stages of infiltration. The proposed model shows good agreement with experimental results and provides a tool for analysis of infiltration kinetics in reactive systems. It may be applied to other systems for different chemistries, properties and geometries to establish process feasibility.
机译：通过原位合成Cu-Mn / TiB {dollar} sb2 {dollar}复合材料，成功实现了反应性无压浸渗（RPI）。经RPI处理的含7至40 v / o TiB {dollar} sb2 {dollar}的Cu-Mn / TiB {dollar} sb2 {dollar}复合材料的微观结构具有良好的微结构（0.5-5 {dollar} mu {dollar} m），并且钢筋分散均匀，室温强度和硬度高。在相对较低的温度（980-1050℃）下自发发生渗透，不需要复杂的加工设备。改变MMC相组成和微观结构的主要因素是增强体形成的焓和相对自由能，初始粉末尺寸，加工温度和增强体的基质润湿性。在Cu-Ti液体和MnB {dollar} sb2 {dollar}之间使用基质辅助置换反应：MnB {dollar} sb2 {dollar} + Cu-Ti {dollar} to {dollar} TiB {dollar} sb2 {dollar} + Cu-Mn可确保在Cu-Mn基体中原位形成TiB {dollar} sb2 {dollar}细颗粒。由于润湿性，该反应还提供了Cu-Ti液体对固体MnB {sb2 {sb2}}预制棒的自发渗透。该过程可以在Cu的熔点以下进行，因为Cu与Mn合金化会降低合金的液相线温度，并导致渗透前沿的扩散熔化。提出并分析了加工过程中微观结构演变的可能机理。研究表明TiB {dollar} sb2 {dollar}是通过界面反应形成的：Ti + MnB {dollar} sb2 {dollar} = TiB {dollar} sb2 {dollar} + Mn。提出了反应性无压渗透的详细动力学模型。该模型评估扩散，渗透和反应过程，并预测渗透速率，反应层厚度随时间的变化，TiB {sb2} sb2 {美元}的形成反应速率以及各组分的浓度分布。反应层。该模型确定了加工参数，例如反应时间和温度，预成型坯被熔体润湿，预成型坯的孔隙率，预成型坯的组成以及增强物的体积分数对渗透动力学的影响。它还建立了渗透的限制阶段。所提出的模型与实验结果显示出良好的一致性，并为分析反应体系中的渗透动力学提供了一种工具。可以将其应用于具有不同化学性质，特性和几何形状的其他系统，以建立过程可行性。

著录项

  • 作者

    Shtessel, Victoria E.;

  • 作者单位

    Drexel University.;

  • 授予单位 Drexel University.;
  • 学科 Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 1996
  • 页码 222 p.
  • 总页数 222
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;
  • 关键词

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