Severe plastic deformation (SPD) is a key processing route for producing ultrafine-grained (UFG) materials that are vital to aerospace, energy, and biomedical applications. However, existing sheet-based SPD methods, such as constrained groove pressing (CGP), are limited by scalability, dimensional rigidity, and nonuniform strain distribution. This study introduces and experimentally validates a novel SPD technique, truncated rectangular pyramid pressing (TRPP), designed to overcome these limitations. TRPP employs a distinctive die geometry that strategically utilizes undeformed zones as inherent lateral constraints during the flattening stage, thereby eliminating the need for external sidewalls. Theoretical analysis shows that the combined shear and bending strains, concentrated in the corner regions of the TRP features, generate a significantly higher equivalent plastic strain than the theoretical maximum achievable by conventional CGP under the same number of deformation passes. Experimentally, commercially pure titanium was processed via TRPP at an elevated temperature of 623 K over four consecutive cycles. The results reveal that four TRPP cycles increased the yield strength by 53% (from 265 MPa to 406 MPa), the ultimate tensile strength by 66% (from 334 MPa to 553 MPa), and the Vickers microhardness by 126% (from 111 HV to 251 HV). Notably, samples subjected to two TRPP cycles exhibited an optimal balance between strength and ductility, achieving a yield strength of 351 MPa (+32%), an ultimate tensile strength of 494 MPa (+48%), a microhardness of 221 HV (+99%), and a ductility of approximately 10%. Overall, TRPP demonstrates a scalable, energy-efficient, and cost-effective SPD process for fabricating highperformance sheet materials suitable for industrial applications.

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