Functional Characterization of Shape Memory CuZnAl Open-Cell Foams by Molten Metal Infiltration

Tuesday, May 18, 2010

Functional Characterization of Shape Memory CuZnAl Open-Cell Foams by Molten Metal Infiltration

S. Arnaboldi, B. Paola, P. Francesca, T. Ausonio, CNR IENI Istituto per l'Energetica e le Interfasi, Lecco, Italy

In the recent years the research for novel material with tailored mechanical properties as well as functional material has encouraged the study of porous materials and metallic foams. The relative quantities and distribution of both, the metal and the voids, can be tailored in order to obtain the desired stiffness, permeability and thermo physical properties. The main parameters to be considered are the relative density of the obtained material, and size, distribution, interconnection of the pores. The main processes used for producing porous materials generally are limited to specific ranges of the cited parameter, so a great effort is devoted to the development of novel synthesis procedure for this material category.

In a previous work, the possibility to manufacture an open cell metal foam of a CuZnAl shape memory alloy by liquid infiltration of leachable bed of silica-gel particles, was proposed and related.

This innovative methodology was based on cheap commercial consumables and a simple technology, focusing on intermediate-density low-cost foams with interesting cost/benefits ratio. To evaluate feasibility and reproducibility of this innovative process, several foamed specimens were obtained and characterized. Microstructural analyses on foamed specimens showed uniform microstructure of ligaments and a very regular open cell foams. Moreover, calorimetric analysis detected a termoelastic martensitic transformation in the foamed material.

In this work, CuZnAl shape memory alloys with different chemical compositions were considered and tested to clarify possible effects of the foaming process on the on the functional properties of the material. Morphological, calorimetric and thermo mechanical analyses were carried out. The results showed the opportunity to produce metal foams of CuZnAl shape memory alloys, with different transformation temperatures and able to recover mono axial compressive deformation up to 3 % in strain.

Summary: In this work, CuZnAl shape memory alloys with different chemical compositions were considered and tested to clarify possible effects of the foaming process on the on the functional properties of the material. Morphological, calorimetric and thermo mechanical analyses were carried out. The results showed the opportunity to produce metal foams of CuZnAl shape memory alloys, with different transformation temperatures and able to recover mono axial compressive deformation up to 3% in strain.