Shape Memory and Superelastic Ceramics at Small Scales

被引:255
作者
Lai, Alan [1 ]
Du, Zehui [2 ]
Gan, Chee Lip [2 ,3 ]
Schuh, Christopher A. [1 ]
机构
[1] MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA
[2] Nanyang Technol Univ, Temasek Labs, Singapore 639798, Singapore
[3] Nanyang Technol Univ, Sch Mat Sci & Engn, Singapore 639798, Singapore
关键词
MARTENSITIC-TRANSFORMATION; ZIRCONIA; TOUGHNESS; SELECTION; BEHAVIOR; ALLOYS;
D O I
10.1126/science.1239745
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Shape memory materials are a class of smart materials able to convert heat into mechanical strain (or strain into heat) by virtue of a martensitic phase transformation. Some brittle materials such as intermetallics and ceramics exhibit a martensitic transformation but fail by cracking at low strains and after only a few applied strain cycles. Here we show that such failure can be suppressed in normally brittle martensitic ceramics by providing a fine-scale structure with few crystal grains. Such oligocrystalline structures reduce internal mismatch stresses during the martensitic transformation and lead to robust shape memory ceramics that are capable of many superelastic cycles up to large strains; here we describe samples cycled as many as 50 times and samples that can withstand strains over 7%. Shape memory ceramics with these properties represent a new class of actuators or smart materials with a set of properties that include high energy output, high energy damping, and high-temperature usage.
引用
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页码:1505 / 1508
页数:4
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