Mechanics and multi-physics of phase transformations in shape memory alloys under extreme dynamic environments

Descripción del proyecto

Dilucidar las aleaciones con memoria de forma sometidas a choques

Las aleaciones con memoria de forma (AMF) modifican su arquitectura atómica en respuesta a estímulos externos. Al alternar entre distintas fases estructurales, estos materiales pueden absorber cantidades masivas de energía o generar potencia mecánica, lo que los convierte en elementos indispensables para la próxima generación de sistemas energéticos sostenibles y de hardware para exploración espacial profunda. Sin embargo, la comprensión de las AMF es limitada. En el proyecto MultiPhaseXtrM, financiado por el Consejo Europeo de Investigación, se pretende superar esta limitación estudiando las AMF en entornos dinámicos extremos. El equipo del proyecto someterá estas aleaciones a impactos multiaxiales que alcanzan presiones de hasta 10 GPa en unas milmillonésimas de segundo. La investigación propuesta consiste en un estudio exhaustivo sobre la cinética fundamental mediante la cual los átomos se reorganizan al ser llevados a sus límites absolutos.

Objetivo

Efficient power generation/absorption will remain a crucial aspect of disruptive technology in a society with rising energy demands for sustenance (e.g. power generation) to scientific curiosity (e.g. space exploration). Multi-functional shape memory alloys (SMAs) form the core of many such technological breakthroughs. The multi-functionality of SMAs originates from solid-solid phase transformations, i.e. changes in the atomic lattice structure, driven by local mechanical, thermal or magnetic fields. Project MultiPhaseXtrM identifies a radically different and unexplored regime for the operation of SMAs — large, multiaxial dynamic impact and shock stresses (up to 10 GPa) within short time scales (down to nanoseconds), referred to as “extreme dynamic environments”. Exploiting multi-physical coupling in SMAs under these extreme conditions could scale up their power conversion capabilities by orders of magnitude.

Two broad scientific questions form the core of Project MultiPhaseXtrM: (1) How do thermodynamic states evolve in SMAs under extreme dynamic environments and coupled thermal/magnetic fields? (2) How do these states drive the evolution of phase transformations at short time scales? Dynamic impact experiments and high-speed instrumentation, developed in house, will probe this multi-scale behavior in single-crystal SMAs under carefully-controlled strain rates and multi-axial stress states, while advancing experimental science towards resolving short length and time scales, simultaneously. Multi-scale data sets will be analysed within continuum theoretical frameworks to discover the kinetic laws for phase transformations across the range of multi-physical conditions explored. The impact of this program will extend beyond, from designing multi-ferroic SMAs with programmable multi-functionality under these extremes, to understanding the role of stress-induced phase transformations in dynamic material strength, material synthesis and extreme geological events.