Thermodynamic predictions of wrought alloy compositions amenable to semi-solid processing

✍ Scribed by A.Maciel Camacho; H.V Atkinson; P Kapranos; B.B Argent

• Book ID: 104403017
• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 771 KB
• Volume: 51
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/s1359-6454(03)00040-5

✦ Synopsis

Semi-Solid Metal (SSM) Processing or Thixoforming is now a commercially successful manufacturing route producing millions of near net-shape parts per annum for the automotive industry. Currently, effort is directed towards developing wrought performance alloys that are amenable to the thixoforming process. Here, the 7000 series Al-Zn-Mg-Cu system has been studied by means of thermodynamic modelling to identify those compositions likely to be most suitable. The non-equilibrium solidification has been determined by using the Scheil equation and the liquid fraction/temperature relationship obtained. The results show the effect of chemical composition and Zn/Mg ratio on the slope of the liquid fraction/temperature curves. As the Zn + Mg + Cu content increases and the Zn/Mg ratio decreases, the slopes of these curves become less steep. The effect of chemical composition, Zn/Mg ratio and temperature on equilibrium phases is also considered. The phases in equilibrium at a given temperature are strongly affected by the Zn/Mg ratio and Cu content.