1.报告会简介
报告人:Jeffrey M. Wheeler(研究员)
时 间:2017年6月6日(星期二) 上午09:00(开始时间)
地 点: 友谊校区公字楼334
主 题: Combinatorial Micromechanics
内容简介: Micromechanical testing has made significant progress in the last few decades. Advances in instrumentation and techniques have developed new geometries for measuring uniaxial strength and fracture toughness at very small length scales. In addition to increasing the test space envelope in terms of smaller sizes, the development of displacement controlled systems has allowed these properties to be investigated over a wide range of strain rates, even within single samples using strain rate jump and stress relaxation techniques. Using new, high speed actuators, the available test space has also been expanded to reach the high strain rate regime ( >103s-1). To complete the testing envelope, significant effort has been spent on achieving high temperature testing, and recently cryogenic temperature testing has also been achieved. By combining all these capabilities, the micromechanical testing envelope has grown to encompass a significant range of testing temperatures (-100 to 600 °C)and over eight orders of magnitude in strain rates (10-5to 103s-1).This creates the opportunity for plastic deformation mechanism mapping of materials at small scales over a wide range of homologous temperatures.
Diffusion couples have long been a fundamental technique in materials science, allowing the exploration of phase diagrams and diffusion constants. With the advent of the Materials Genome Initiative, diffusion couples and multiples are now being used as a high throughput means to investigate a wide range of materials properties. However, so far only the most fundamental micromechanical technique (nanoindentation) has been used to interrogate mechanical properties of diffusion couples. Here, the potential of applying advanced micromechanical techniques to diffusion couples will be demonstrated in the case of the Al-Cu binary system.
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党委研究生工作部
材料学院
2017年6月2日
报告人简介
Jeffrey Wheeler博士2005年本科毕业于美国伊利诺伊理工学院,2009年在英国剑桥大学拿到博士学位,随后在英国剑桥大学高登实验室开展博士后研究。2010年开始,在瑞士联邦材料实验室(EMPA)进行关低温和高温微纳米力学设备的研发,同时利用先进表征手段研究材料在极端环境下的变形行为。2015年加入瑞士苏黎士联邦理工学院,成为材料学院纳米冶金实验室的研究员,目前主要关注共价键材料的的尺寸效应,以及温度和应变速率敏感性。Wheeler研究员参与了多个研究项目,已发表51篇国际性期刊文章。