Processing, Microstructure and Superplasticity in Al-Mg-Mn Alloys
Abstract
A thermomechanical processing (TMP) schedule developed in previous work was modified to provide for an increasing strain and strain rate with each rolling pass. Three alloys, Al-10Mg, Al-10Mg-0.2Mn, and Al-10Mg-0.5Mn (compositions in wt. pct.), were processed utilizing this schedule. Samples were obtained following various rolling passes for subsequent microscopy analysis. Materials in both the as-rolled condition and following 25 minutes of annealing were studied. Utilizing backscattered imaging techniques with the scanning electron microscope, the microstructural evolution of these alloys during the TMP was studied. Second phase particles were observed to precipitate on grain boundaries and deformation structures in the intermediate stages of the TMP. In addition, second phase precipitates developed on MnAl6 particles through heterogenous nucleation in the Manganese containing alloys. Particle stimulated nucleation of recrystallization was observed in the latter stages of the TMP as precipitate particles coarsened. Tensile testing at 300 degrees C demonstrated the superplastic response of each alloy, and showed that the addition of Manganese enhances superplastic response. Strain rate sensitivity coefficients were observed to initially decrease with increasing strain, but then increased with further straining.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1991
- Accession Number
- ADA246488
Entities
People
- Chris D. Meyer
Organizations
- Naval Postgraduate School