Deformation Mechanisms and Formability Window for As-Cast Mg-6Al-2Ca-1Sn-0.3Sr Alloy (MRI 230D)

Research output: Journal contributionsJournal articlesResearchpeer-review

Authors

  • Kalidass Suresh
  • Kamineni Pitcheswara Rao
  • Dharmendra Chalasani
  • Prasad Yellapregada Venkata Rama Krishna
  • Norbert Hort
  • Hajo Dieringa

The hot deformation characteristics of MRI 230D alloy have been evaluated in the temperature range 260-500 °C and strain rate range 0.0003-10 s−1, on the basis of processing map. The processing map exhibited two domains in the ranges: (1) 300-370 °C and 0.0003-0.001 s−1 and (2) 370-480 °C and 0.0003-0.1 s−1. Dynamic recrystallization occurs in the both domains with basal slip dominating in the first domain along with climb as recovery process and second-order pyramidal slip dominating in the second with the recovery by cross-slip. In Domains (1) and (2), the apparent activation energy values estimated using the kinetic rate equation are 143 and 206 kJ/mole, respectively, the first one being close to that for lattice self-diffusion confirming climb. It is recommended that the alloy is best processed at 450 °C and strain rates less than 0.1 s−1, where non-basal slip and cross-slip occur extensively to impart excellent workability. The alloy exhibits flow instability in the form of adiabatic shear band formation and flow localization at lower temperatures and higher strain rates. Forging of a cup-shaped component was performed under various conditions, and the results validated the predictions of the processing map on the workability domains as well as the instability regimes.

Original languageEnglish
JournalJournal of Materials Engineering and Performance
Volume27
Issue number3
Pages (from-to)1440-1449
Number of pages10
ISSN1059-9495
DOIs
Publication statusPublished - 01.03.2018
Externally publishedYes

    Research areas

  • hot forging, hot workability, kinetic analysis, Mg-Al-Ca-Sn-Sr alloy, microstructure, processing map
  • Engineering