Investigation of the Superplastic Behavior of ۱۰۵۰ Aluminum Strip Processed by the ECAP-Pull Method

This study introduces a novel, energy-efficient severe plastic deformation (SPD) technique termed equal channel angular pulling (ECAP-Pull). This method replaces the conventional pressing action with a tensile force, enabling the continuous processing of long strips. Commercial purity AA۱۰۵۰ aluminum strips were successfully processed for up to eight passes using this method. Quantitative microstructural analysis revealed a remarkable grain refinement, with the average grain size reduced from an initial ۷۷.۷۶ µm to ۲۱.۲۸ µm and ۱۰.۷۲ µm after four and eight passes, respectively, corresponding to an ۸۶% total reduction. This refinement produced a microstructure ideally suited for superplastic forming, dominated by high-angle grain boundaries. Subsequent uniaxial tensile tests demonstrated exceptional superplasticity, with maximum elongations to failure of ۳۴۰% and ۵۸۰% achieved at ۶۸۳ K and a strain rate of ۲×۱۰⁻⁴ s⁻¹ for the four-pass and eight-pass samples, respectively. The eight-pass sample also exhibited a lower flow stress, confirming a transition of the dominant deformation mechanism to grain boundary sliding. The ECAP-Pull process represents a significant advancement by overcoming the batch-processing bottleneck of traditional SPD methods, offering a scalable and industrially viable route for producing superplastic sheet materials.

کلیدواژه ها:

Superplastic behavior ، Severe plastic deformation (SPD) ، ECAP-Pull