Tuning the pyro- and piezoelectric voltages in 3D-printed PVDF/FSMA composites controlled by the martensitic transformation induced strain

Abstract 3D-printed PVDF-based composites containing Ni 45 Mn 36.7 In 13.3 Co 5 ferromagnetic shape-memory alloy (FSMA) microparticles (MPs) were fabricated and investigated to evaluate their pyro- and piezoelectric performance controlled by the martensitic transformation (MT) of the MPs. The composites exhibit a clear increase in the direct pyro- and piezoelectric voltage with temperature, demonstrating the emergence of electroactive behaviour in 3D-printed PVDF-FSMA systems. Furthermore, the MT of the embedded FSMA particles induces internal strain fields that significantly modify the electrical response, producing a voltage drop near the MT temperature. This additional ‘smart’ functionality is fully tunable through an external magnetic field, which enhances the MT-induced strain and yields a controlled modulation of the pyro- and piezoelectric output. These findings establish 3D-printed PVDF-FSMA composites as versatile multifunctional materials whose electro-thermo-mechanical response can be magnetically tailored, opening new pathways for adaptive sensors, actuators, and energy-harvesting devices. Moreover, a previously unreported damping peak near 280 K, linked to interactions among the amorphous phase, the α / β crystalline phases, and FSMA inclusions, is identified.