[责任编辑]李敏妍　[信息提供]材料学院 金学军

报告题目：国际材料前沿讲座：Synthesis and Consolidation of Nanostructured Metallic and Metal Matrix Composite Powders by Thermomechanical Processing

报告人：Deliang Zhang
　　　　Waikato Centre for Advanced Materials (WaiCAM), School of Engineering,
　　　　University of Waikato, Hamilton, New Zealand
　　　　“千人计划”入选者

报告时间：7月9日周五上午9：30-11：30

报告地点：材料A楼308会议室

联系人：金学军 教授

ABSTRACT

Synthesis and Consolidation of Nanostructured Metallic and Metal Matrix Composite Powders by Thermomechanical rocessing
Deliang Zhang Waikato Centre for Advanced Materials (WaiCAM), School of Engineering, University of Waikato, Hamilton, New Zealand Nanostructured metallic and metal matrix composite powders can be effectively produced  by high energy mechanical milling (HEMM) which is one of the low temperature thermomechanical processing processes. In order to minimise the grain growth and other microstructural changes during consolidation of the nanostructured powders, it is necessary to apply heat, pressure and plastic deformation simultaneously to accelerate the processes of densification and interparticle atomic bonding.

For this reason, thermomechanical processing of the powder compacts is essential for the consolidation of nanostructured metallic and metal matrix composite powders. This talk will show and discuss how the starting powder mixture composition (and mechanical properties as well) affect the size, morphology and microstructure of Cu-(2.5-10)vol.%Al2O3 and Al-(2.5-10)vol.%Al2O3 nanocomposite, Ti/Al based composite powder particles and Cu-(1-4)at%Pb alloy powders produced by HEMM, and how this effect can be utilised to avoid or minimise the use of process control agent (PCF) which, in most cases, is an contaminant.  The talk will also show the microstructure, strength and ductility of samples produced by consolidation of milled Cu-(2.5-10)vol.%Al2O3 nanocomposite powders using a combination of hot ressing and powder compact forging (PCF) (without using containers). For comparison, the microstructure and mechanical properties of samples produced by consolidation of ultrafine grained and coarse grained Cu, Ti and Ti-6wt%Al-4wt%V alloy powders by PCF and powder compact extrusion (PCE) will be shown and discussed. In the powder consolidation research, tensile testing and fracture surface examination were extensively used to determine the level of interparticle atomic bonding. Some theoretical considerations have been made in relation to the roles of new particle surfaces formed through plastic deformation in the process of establishing interparticle atomic bonding. If time allows, some of the results from these considerations will also be highlighted in the talk.

Biography

　　张德良教授(Professor) 2008年2月-现在 新西兰 怀卡托大学(The University of Waikato)，1981年9月-1985年7月中国东北工学院(现名：东北大学) 金属铸造工学学士。1987年9月-1990年9月英国牛津大学冶金及材料科学(1991年1月获博士学位)。

　　张德良教授是国际亚稳材料制备和加工，钛合金粉末制备和固结等科研领域知名的材料科学家。在用高能机械研磨法制备和加工纳米结构金属基复合材料粉末学术研究和技术创新上有很高的造诣。深入、系统地阐述了金属－金属、金属－陶瓷混合粉末高能球磨过程中粉末颗粒内部复合结构的形成和细化过程，以及此复合结构的细化程度对粉末颗粒内部相与相之间反应的热力学及动力学的影响。该成果于2004年发表在影响因子18.1 的“材料科学进展(Progress in Materials Science)” 上。五年来被引107次。另外，他澄清了对微米级和纳米级复合结构内金属(比如铝)和金属氧化物(比如二氧化钛，氧化铜) 之间在高能机械研磨和热处理过程中 氧化还原反应的理解，并提出了三个材料加工工艺新概念。基于这些材料加工工艺新概念，他发明了三项生产粉末材料新工艺， 并因此成为四项国际专利申请，两项美国专利及两项新西兰专利的{dy}(或{wy})发明人。两项技术已经被新西兰的Titanox公司采用，并引起新西兰贸易及企业发展部的高度重视。其中一项钛合金粉末生产技术已成为在新西兰发展钛合金产品生产工业的骨干技术。

　　张教授的研究工作深化了对 Ti(Al,O)-Al2O3,TixAly(O)-Al2O3 Ti2AlC/TiC/Al2O3自生复合材料生成过程及此种复合材料显微结构-性能关系的理解，并深入探讨了金属纳米尺寸液滴的凝固和纳米尺寸固体颗粒的溶化。五年内张教授共发表学术论文77篇，主持编辑《先进材料研究》(Advanced Materials Research)期刊和《国际现代物理期刊 B》 (International Journal of Modern Physics B)特集各一集，以及参与编辑《材料科学与工程A》期刊特集一集。自1990年所发表的学术论文总共被引1098次。在新西兰怀卡托大学创建了国际{yl}的金属基合金及复合材料粉末制备，加工和固结研究实验室，并领导科研团队自2000年以来承担四项新西兰国家重大科研课题(其中两项已完成)。