丹麦技术大学余天博博士讲学通知

   应3777金沙娱场城耿林教授、范国华副教授邀请，丹麦技术大学材料科学与先进表征研究所余天博研究员近日访问我校，并将进行学术报告，具体安排如下：

报告题目：基于投射电子显微技术的强变形金属的回复新机制研究

(1. Recovery by triple junction motion in heavily deformed metals; 2. Observation of a new dynamic recovery mechanism during high strain deformation)

   报告人：余天博研究员/丹麦技术大学
   时间：2015年10月14日上午9:00
   地点：材料楼522会议室

报告内容：

   A number of processes may occur during recovery, which reduce the stored energy and coarsen the structure, paving the way for the nucleation of recrystallization. In this review, recovery is discussed based on the initial deformed structure. Recovery in samples deformed to low-to-medium strains is briefly considered, whereas recovery in samples deformed to much higher strains is discussed in more detail. An example is Al, where a new and important recovery mechanism is triple junction motion, which can remove thin lamellae and consequently increase the thickness of neighbouring lamellae. This recovery mechanism therefore coarsens the structure and causes a gradual transition from a lamellar to a near equiaxed structure preceding recrystallization. This mechanism is discussed in conjunction with structural pinning, which stabilizes the coarsening microstructure, thereby balancing the forces controlling the rate of recovery by triple junction motion. Operation of triple junction motion in other heavily deformed metals, such as Ni and Cu, is also briefly discussed.

   专家简介：余天博，丹麦技术大学研究员。2002年~2006年清华大学本科、硕士；2012年获丹麦技术大学博士学位。长期从事晶体取向分析与金属形变微结构分析，在利用电子显微分析技术研究金属回复再结晶行为方面取得了大量原创性结果，在《Acta Materialia》、《Philosophical Magazine》、《Proceedings of the Royal Society A》等杂志先后发表论文30余篇。