题目：Dynamic materials response at extreme conditions: phase changes, plasticity, damage, chemical reactions, and microstructural effects
报告人：罗胜年，四川大学，中组部创新人才计划教授 （8907）
时间： 7月9日下午3:00-4:00
地点： 力学一楼二楼239会议室
报告人简介：
罗胜年，四川大学顶峰多尺度科学研究所所长，物理与技术学院教授，国家“创新人才计划”学者。他在中国科学技术大学和加州理工学院分别获得学士和博士学位，曾任美国洛斯阿拉莫斯国家实验室物理部永久性物理学家。他的研究方向是极端条件下材料的动态响应。他利用实验、数值和理论手段，研究动态加载和先进诊断技术，及冲击响应的微结构效应，包括损伤与断裂、塑性、化学反应、相变和状态方程。他从理论上解决了过热熔化问题并提出精确实用的过热（过冷）－加（降）温率模型；他第一个提出并领导实现气炮和霍普金森杆加载下、同步辐射X射线相衬成像和劳埃衍射，并最高达到百皮秒和微米的分辨率。他在国际专业刊物上发表90多篇学术论文，并多次在国际学术会议上作邀请报告。他曾获得美国能源部国家核安全管理机构的防卫项目杰出奖和洛斯阿拉莫斯国家实验室院长博士后奖学金等。
报告内容简介：
One of the grand challenges in materials physics is materials response to dynamic loading such as shock waves, due to the highly transient nature and extremely complex microstructure effects. Dynamic responses are inherently multiscale, and the measurements at ns and sub-mm scales are particularly challenging. In this talk, we present our endeavors along this line, including phase changes, plasticity, damage, and hotspot formation in energetic materials, as well as the development of ultrafast X-ray diagnostics. The microstructure effects on dynamic responses focus on grain boundaries, investigated with dynamic experiments and molecular dynamics simulations. The materials include metals, metallic glasses, energetic materials, and gases. On the diagnostics development, we address synchrotron-based ultrafast X-ray phase contrast imaging and diffraction under gas gun and Hopkinson bar loading. While significant new insights have certainly been gained into dynamic materials response, developing predictive models incorporating microstructure effects remains as a daunting task, and calls for multiscale, multiphysics approaches, which are unfortunately still unknown.
