天元杰出讲堂 | Highly Irregular Microstructures and TN Congurations
报 告 人： John Ball Member of Academia Europaea
所在单位： Heriot-Watt University Maxwell Institute for Mathematical Sciences, Edinburgh
报告地点： Zhengxin building 209
报告时间： 2025-07-24 09:00:00
报告简介：

Remarkable martensitic microstructures are observed in the alloy Ti76Nb22Al2, which undergoes a cubic to orthorhombic transformation with six martensitic variants Ui =UT i >0having middle eigenvalue 2(Ui) very close to 1. Assuming that 2(Ui) = 1 there are exactly 12 matrices in the set of energy wells 6 i=1 SO(3)Ui that are rank-one connected to 1. This set of 12 matrices has no rank-one connections. We attempt to understand the observed microstructures by studying gradient Young measures, exact gradients and TN-con gurations supported on these 12 matrices. This is joint work with Tomonari Inamura and Francesco Della Porta.
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主讲人简介：
John Macleod Ball is a professor at the University of Oxford in the UK and Heriot-Watt University. He is a fellow of the Royal Society of the UK, a member of the European Academy of Sciences, a fellow of the American Mathematical Society, a fellow of the Royal Society of Edinburgh, a foreign member of the French Academy of Sciences, and a foreign member of the Norwegian Academy of Sciences. He has held positions such as the chair of the Fields Medal Committee (2006), the president of the International Mathematical Union (2003-2006), a member of the Executive Committee of the International Mathematical Union (2007-2010), a member of the first Abel Prize Committee, the president of the Edinburgh Mathematical Society, and the president of the London Mathematical Society. As an internationally renowned mathematician, Sir John Ball holds a significant academic position in the global mathematics community. He has made outstanding contributions in the fields of calculus of variations, partial differential equations, infinite-dimensional dynamical systems and their applications in nonlinear mechanics, the mathematical theory of nonlinear elasticity, and the mathematical theory of liquid crystals.