Recovery and recrystallization in the superplastic deformation of AA5182

Abstract

The coarse-grained Al alloy AA5182 exhibits poor superplasticity with a maximum elongation to failure not exceeding 220 % at 450 C and at 10 -2 s -1. The low values of the strain rate sensitivity indicate that the dislocation velocity is quite high and necking is developed quite soon during extension. The size (often exceeding 1 lm) and the distribution of the precipitates render them incapable of pinning the subgrain boundaries efficiently. As a result recovery and reconstruction by grain refinement occurs only within the necking region where the applied stress is concentrated. A fabrication method which will be able to introduce a large number of submicron sized precipitates will most likely result in sufficient pinning of the subgrain boundaries. This will promote recovery and reconstruction to take place more uniformly in the material rendering it appreciably superplastic.

Efficient Coarse‐Grained Superplasticity of a Gigapascal Lightweight Refractory Medium Entropy Alloy

“…Actually, the low temperature can significantly prohibit the dynamic recrystallization that dominates the coarse‐grained superplasticity. [ 97 , 98 ] Thus, the strain‐rate sensitivity of the plasticity in the HC‐LRMEA is not significantly. Nevertheless, when the superplastic deformation occurred at 1173 K, the low strain rate (10 −3 s −1 ) deformation can enhance the elongation of HC‐LRMEA to be larger than the high strain rate (10 −2 s −1 ) deformation case by ≈20% (Figure 2a ; Figure S4 , Supporting Information).…”

Deformation mechanism of aluminum–magnesium alloys at elevated temperatures

“…1a and middle and bottom of Fig 1b corresponding, most likely, to precipitates. These were located very often close and/or exactly at the GB interfaces and were identified as being rich in Mn, Cu, Fe, and Si and depleted in Al and Mg. Their size most often was between 0.5 and 1.5 lm, but could in rare occasions reach 10 lm [9]. Size distribution and density of precipitates was done from TEM pictures.…”

Annealing response of AA5182 deformed in plane strain and equibiaxial strain paths

“…The annealing treatment, which can incorporate microstructural changes in the materials through possible recovery, recrystallization and grain growth, can be used to improve the formability of Al-Mg alloys [9][10][11][12][13][14][15]. Separate kinetics models were used to distinguish static recovery and recrystallization processes during annealing of AA5182 prestrained to different strain levels [16].…”