Adjustable and negative thermal expansion from multilayered systems

• Published in: Physica status solidi. PSS-RRL. Rapid research letters 2010-06, Vol.4 (5-6), p.133-135
• Main Authors: Grima, Joseph N., Oliveri, Ludovica, Ellul, Brian, Gatt, Ruben, Attard, Daphne, Cicala, Gianluca, Recca, Giuseppe
• Format: Article
• Language: English
• Subjects: Adjustable; Bonding; Condensed matter: structure, mechanical and thermal properties; Construction; Construction materials; Exact sciences and technology; layered compounds; Physical properties of thin films, nonelectronic; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); System built; Thermal expansion; Thermal properties; Thermal stability; thermal effects; Thin films
• ISSN: 1862-6254; 1862-6270; 1862-6270
• DOI: 10.1002/pssr.201004076

A construct in the form of a multi‐layered system built from conventional materials having different mechanical and thermal properties is proposed. This construct can exhibit pre‐determined values of thermal expansion which could also be negative. It is shown that for maximising negative thermal expansion (NTE) there should be a combination of thin layers of stiff materials having a high positive coefficient of thermal expansion (CTE) bonded with thicker layers of a soft material having low CTE values and, more importantly, having Poisson's ratio as high as possible. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) A multi‐layered system built from conventional materials having different mechanical and thermal properties is proposed. This construct can exhibit predetermined values of the coefficient of thermal expansion (CTE) which could also be negative (NTE), a property which is highly desirable. It is shown that for maximising NTE, there should be a combination of thin layers of stiff materials having a high positive CTE bonded with thicker layers of a soft material having low CTE values and, more importantly, having Poisson’s ratio as high as possible.