Microstructure and electrical resistivity features in Al-Al 4 C 3in-situ composite after attrition milling and double sequence of compaction and high temperature treatment


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Ozdemir A. T. , Bostan B.

Kovove Materialy, vol.50, no.2, pp.89-95, 2012 (Journal Indexed in SCI Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 50 Issue: 2
  • Publication Date: 2012
  • Doi Number: 10.4149/km_2012_2_89
  • Title of Journal : Kovove Materialy
  • Page Numbers: pp.89-95

Abstract

An Al-based composite powder (Al-2%C) was prepared by mechanical alloying (MA). Mixed powders were cold compacted and annealed using two consecutive treatments. Microstructure progresses in both; the as-milled and the as-pressed and annealed conditions were characterized by X-ray diffractometry (XRD) and transmission electron microscopy (TEM). During MA, C diffused into Al to form a solid solution. However, for MA, primary compaction and 1 h sintering at 650°C was insufficient to synthesize Al with C. Only after secondary pressing and long-time annealing at 550°C, fine precipitates of Al 4C 3were formed throughout the matrix. Increase in Al 4C 3dispersion and stabilization of a dense dislocation substructure was the main source of systematic rise in both electric resistivity and hardness.