题目：Status and future perspectives of Wire Arc Additive Manufacturing 

报告人：李会军 教授（澳大利亚伍伦贡大学） 

时间：2023年11月21日（周二），10：00-12：00 

地点：师昌绪楼403 

报告摘要： 

Additive manufacturing (AM) builds up a component through the deposition of materials layer-by-layer instead of starting with an over dimensioned raw block and removing unwanted materials, as practised in conventional subtractive manufacturing. With the development of AM technology, the current focus has shifted to producing high quality metal components of complex shape that can meet the demanding requirements of aerospace, defence, and automotive industries. DED - Arc additive manufacturing is by definition a wire-feed/powder feed and arc-based additive manufacturing that uses either the gas tungsten arc welding (GTAW) or the gas metal arc welding (GMAW) process has drawn the interest of the research community in recent years due to its high deposition rate. This technique has been presented to the aerospace manufacturing industry as a unique low cost solution for manufacturing large size structures through significantly reducing both product development time and “buy-to-fly” ratios. University of Wollongong’s research includes the production of large-scale complex components, as well as breakthroughs in the fundamental understanding of the solidification process and high temperature behaviour mechanisms. This should provide significant benefits, such as enhancement of Australia’s capacity in advanced materials and manufacturing and strengthening the country’s world leading position in the area. 

Some challenges for DED-Arc additive manufacturing include the microstructural control, standard development, and qualification and certification process. At the microstructural scale, the repeated thermal cycles during AM processing result in a noticeable in-homogenisation of microstructural development. Micro-segregation, lattice distortion, and intensive texture are all indicators of material uniformity. Especially, in AM processes, elemental micro-segregation during solidification from a previous melt track results in grain boundaries and/or interdendritic areas having a depressed solidus point due to the changed chemical composition. This will cause the formation of non-uniform microstructures and types of detrimental non-equilibrium precipitates, leading to inferior strength in these areas. Researchers at University of Wollongong have developed an innovative WAAM fabrication method for large expensive metal components for industry, which is capable of dealing wide range of materials, including steels, Al alloys, Cu alloys, Ni based super alloys and intermetallic alloys. This presentation focuses on the microstructure manipulation, some key points on AM standards development and process qualification. 

报告人简介： 

Senior Professor Huijun Li is currently working at University of Wollongong; he is the Associate Dean – Higher Degree Research at Faculty of Engineering and Information Sciences. He has over 26 years of research experience in materials science and engineering. This includes expertise in the use of electron microscopy to study the microstructure of materials (particularly metals and ceramics) in areas such as phase transformations and structural evolution, additive manufacturing. He also has extensive experience in mechanical tests, failure analysis and materials development, as well as detailed knowledge of crystallography, welding metallurgy, line pipe steels, nickel based alloys, high entropy alloys, and shape memory alloys. 

As a Certified Materials Professional (CMatP) in Australia, Prof Huijun Li obtained a PhD degree in 1996 from the University of Wollongong; He has published 7 book chapters and more than 600 papers over his career in the field of additive manufacturing, welding metallurgy, new alloy development, surface engineering, nuclear materials and microstructure characterization. His publication has attracted more than 16300 citations with h-index 62 in Scopus, and h-index 70 with more than 21600 total citations in Google Scholar (October 2023). 

In 1995, he joined CRC Materials Welding and Joining as a postdoctoral research fellow at University of Wollongong. In 2000, he took a research scientist position at Materials Division, ANSTO (Australian Nuclear Science and Technology Organisation), he worked on a wide range of research projects in conjunction with the CRC Welded Structures, CRC CAST3, CRC Rail, British nuclear research organisations and American national laboratories. During this period, Prof Li pioneered research on 9-12% Cr creep resistant steels in Australia. Prof Li started working at University of Wollongong from July 2008; he is heavily involved in research work with Defence Materials Technology Centre (DMTC), Energy Pipeline CRC (EPCRC), Baosteel Australia Joint Centre (BAJC), and Australian Rail Industry, in particular, Sydney Trains. Prof Li won 45 research/commercial grants (with total more than A$20 million) from government and industry sectors since joining UOW in 2008. 

Prof Li has been supervising (or co-supervising) more than 50 PhD students and 14 postdoctoral fellows; he is the chief investigator of over 40 research projects supported by DMTC, EPCRC, BAJC, Australian Research Council (ARC), Australasian Centre of Rail Institute (ACRI), New South Wales Transportation and other industry sectors. In conjunction with Prof John Norrish and Prof Zengxi Pan, he established wire arc additive manufacturing research at University of Wollongong. 

Prof Li was awarded Australian Museum Eureka Prize for Outstanding Science in Safeguarding Australia, 2013, Australia Endeavour Fellowship 2014, and Defence Materials Technology Centre - Capability Improvement Award in 2014 and 2016. He was named in the 2019 Australian Research magazine as Australian Field leader in both Manufacturing & Machinery and Metallurgy.  He has also received UOW Vice Chancellor Award - Research Partnership and Impact Award for the years 2019 and 2023. Prof Li has been recognised as Australia’s top researcher in metallurgy in 2020, 2021, 2022 and 2023 again. Prof Li is currently serving as a Technical Committee Member for both “Standards Australia, MB-028, Additive manufacturing” and “ISO Standards, ISO/TC 261 - Additive manufacturing” since 2020. The joint DMTC shipbuilding project in which Prof Li participated as a chief investigator has earned a High Commendation award at INDO PACIFIC 2022 International Maritime Exposition, this project also won “The Defence science and technology enterprise collaboration award” at the Australian Defence Science, Technology and Research Summit (ADSTAR) July 2022. In 2023, Prof Li was promoted to Senior Professor at University of Wollongong, and in the same year, he was elected as a Member of Australian Research Council (ARC) College of Experts. Prof Li has earned coveted spots in the prestigious Top 2% Most Influential Scientists list by Stanford University for both career-long and the year 2023. 

　　报告人简介： 

　　李会军教授1996年毕业于澳大利亚伍伦贡大学，获工学博士学位。现任澳大利亚伍伦贡大学工程与信息科学研究院副院长、工程材料焊接研究中心主任、博士生导师、终身教授。长期从事低合金高强钢、能源材料、核反应堆材料、高温抗蠕变钢、高熵合金等材料的焊接冶金、增材制造及电子显微学表征、失效分析等方面的研究，累计发表学术论文600余篇，Scopus引用16300余次，H因子达到62。完成了澳大利亚联邦政府、CRC协作研究中心、材料研究中心、澳洲铁路创新研发中心等单位资助的四十余个重大项目，相当一部分研究成果实现工程应用。基于在金属材料焊接增材制造领域的突出贡献，李教授获得了许多荣誉，比如2013年获得了澳大利亚最高科学奖—尤里卡奖（Eureka Award），从2020年至2023年连续获得澳大利亚冶金领域顶尖学者奖，入选斯坦福大学评选的Top 2%最具影响力科学家榜单，李教授也于今年获得了伍伦贡大学的高级教授（Senior Professor）荣誉，并当选为澳大利亚研究理事会会士。