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Characterisation of phase segregation during back extrusion of ZA27 semisolid alloy

Mola, J ; Sharif University of Technology | 2007

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  1. Type of Document: Article
  2. DOI: 10.1179/174328407X158523
  3. Publisher: 2007
  4. Abstract:
  5. Effort was made to characterise segregation tendency of mechanically stirred ZA27 alloy with back extrusion as a thixoforming process. At sufficiently high ram speeds, at which liquid phase flows forcefully, pooling of the heavy liquid phase owing to gravitational segregation contributes to homogeneity of back extruded products in terms of solid phase distribution, The amount of this contribution depends on the contact time of this liquid with solid skeleton during liquid exertion to the clearance. Hence, at high ram speeds, small rams which demand taller initial slugs are more efficient in minimising the segregation. However, in the case of low speed back extrusion tests, liquid impotency gives rise to higher performance of the ram which sooner induces combined flow of both phases and thus, thick rams are advantageous over thin ones. © 2007 Institute of Materials, Minerals and Mining
  6. Keywords:
  7. Extrusion ; Metal forming ; Phase transitions ; Segregation (metallography) ; Back extrusion ; Mechanical stirring ; Phase segregation ; Semisolid processing ; ZA27 alloy ; Mechanical alloying
  8. Source: Materials Science and Technology ; Volume 23, Issue 1 , 2007 , Pages 113-118 ; 02670836 (ISSN)
  9. URL: https://www.tandfonline.com/doi/abs/10.1179/174328407X158523