Metallurgical Transactions A

, Volume 23, Issue 8, pp 2223–2230

Processing map for hot working of powder

  • B. V. Radhakrishna Bhat
  • Y. R. Mahajan
  • H. Md. Roshan
  • YVRK Prasad
Mechanical Behavior

DOI: 10.1007/BF02646015

Cite this article as:
Radhakrishna Bhat, B.V., Mahajan, Y.R., Roshan, H.M. et al. MTA (1992) 23: 2223. doi:10.1007/BF02646015

Abstract

The constitutive flow behavior of a metal matrix composite (MMC) with 2124 aluminum containing 20 vol pct silicon carbide particulates under hot-working conditions in the temperature range of 300 °C to 550 °C and strain-rate range of 0.001 to 1 s-1 has been studied using hot compression testing. Processing maps depicting the variation of the efficiency of power dissipation given by [2m/(m + 1)] (wherem is the strain-rate sensitivity of flow stress) with temperature and strain rate have been established for the MMC as well as for the matrix material. The maps have been interpreted on the basis of the Dynamic Materials Model (DMM). [3] The MMC exhibited a domain of superplasticity in the temperature range of 450 °C to 550 °C and at strain rates less than 0.1 s-1. At 500 °C and 1 s-1 strain rate, the MMC undergoes dynamic recrystallization (DRX), resulting in a reconstitution of microstructure. In comparison with the map for the matrix material, the DRX domain occurred at a strain rate higher by three orders of magnitude. At temperatures lower than 400 °C, the MMC exhibited dynamic recovery, while at 550 °C and 1 s-1, cracking occurred at the prior particle boundaries (representing surfaces of the initial powder particles). The optimum temperature and strain-rate combination for billet conditioning of the MMC is 500 °C and 1 s-1, while secondary metalworking may be done in the super- plasticity domain. The MMC undergoes microstructural instability at temperatures lower than 400 °C and strain rates higher than 0.1 s-1.

Copyright information

© The Minerals, Metals and Materials Society, and ASM International 1992

Authors and Affiliations

  • B. V. Radhakrishna Bhat
    • 1
  • Y. R. Mahajan
    • 1
  • H. Md. Roshan
    • 2
  • YVRK Prasad
    • 3
  1. 1.Defence Metallurgical Research LaboratoryHyderabadIndia
  2. 2.Department of Metallurgical EngineeringIndian Institute of TechnologyMadrasIndia
  3. 3.Department of MetallurgyIndian Institute of ScienceBangaloreIndia