Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556914
Title: Development of hypereutectic Al-Si based P/M alloys
Author: Su, Shei Sia
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2012
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Abstract:
The compaction, sintering and heat treatment processing conditions for the commercial powder, Ecka Alumix 231 with the nominal composition of Al-15Si-2.5Cu-0.5Mg(wt%) have been optimized in this study. It has been found that densification of Ecka Alumix 231 depended largely on the sintering atmosphere and the amount of liquid phase presented. Sintering in nitrogen atmosphere was found to be beneficial due to the formation of AIN which later induced pore filling effect. Presence of hydrogen in the sintering atmosphere, however, was not desirable. Decomposition of MgH2 at higher temperature was suggested to increase the pore pressure and caused detrimental effect on compact densification. The effects of alloy additions (i.e. Cu and/or Ni) on sintering and heat treatment response were also investigated in this study. Addition of copper was found to enhance the sintering response by a significant increase in the sintered density,reduced the peak ageing temperatures and time. Nickel addition, however, was detrimental to both sintering and heat treatment response since it reduced the amount of copper content dissolved in the α-aluminum due to the formation of Al\(_3\)(Ni,Cu)\(_2\) phase. The precipitation sequence for Al-Si-Cu-Mg-(Ni) was suggested to be: Supersaturated solid solution (SSS)→GP zones → θ” → θ’ → θ.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.556914  DOI: Not available
Keywords: TN Mining engineering. Metallurgy
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