報告題目：Additive manufacturing of ultrafine-grained high-strength titanium alloys
報告人：邱冬 教授
主持人（邀請人）： 王慧遠 教授
報告時間：2019年12月18日14:00-16:00
報告地點：南嶺校區逸夫機械材料館209學術報告廳
主辦單位：伟德bv1946、汽車材料教育部重點實驗室
摘要：
Additively manufactured (AM) titanium alloys have been used in numerous applications, in particular in the biomedical and aerospace industries due to the greater material efficiency and enhanced design flexibility. However, for many conventional titanium alloys, the AM process usually results in a microstructure comprised of coarse columnar grains, which often leads to undesirable anisotropic mechanical properties. In contrast to other common engineering alloys, such as aluminium, there is no commercial grain refiner, containing potent inoculants that can survive in liquid titanium, able to control microstructure effectively. To address this challenge, we have developed a novel technique for AM by using Ti-Cu alloys with a high constitutional supercooling capacity that overrides the negative effect of a high thermal gradient in the melt pool during AM. Through this approach, it is shown that an as-printed Ti-Cu alloy specimen is comprised of fully equiaxed, fine grained microstructure without any special process control or additional subsequent treatment. The new AM Ti-Cu alloys also display promising mechanical properties, compared to conventional alloys under similar processing conditions, due to the formation of an ultrafine eutectoid microstructure by taking full advantage of the high cooling rates and multiple thermal cycles in the AM process. We anticipate that this approach will be equally applicable to other eutectoid forming alloy systems.
報告人簡介：
邱冬，教授，2005年在清華大學材料科學與工程系獲得工學博士學位，之後前往澳大利亞昆士蘭大學先後以UQ Postdoc Fellow和 Australian Research Fellow的身份從事鎂合金、鋁合金、鋅合金以及鐵素體/奧氏體鋼等多種工程合金凝固過程中高效晶粒細化劑的開發。2015年被皇家墨爾本理工大學（RMIT）聘為校長特聘高級研究員，開始介入金屬3D打印（增材制造）領域，現在主要從事适合增材制造特點的新型工程合金的設計與開發，以及對3D打印過程中微觀組織的調控與優化。截止到2019年12月，邱冬博士以主要參與人的身份共獲得4次澳大利亞自然科學基金（ARC Discovery Project）和1次應用創新基金（ARC Linkage Project）的資助，發表了80篇經同行評議的期刊論文，其中包括1篇以共同一作身份發表在Nature正刊，以及16篇論文發表在物理冶金領域知名期刊Acta Materialia上，在Scopus⚜⭐〰✝引擎上論文被引用總數達1900餘次，H因子為25。現擔任物理冶金學報（Metallurgical and Materials Transaction A）審稿委員會委員（key reader），澳大利亞自然科學基金評審專家，2017年被伟德bv1946官网聘為“唐敖慶”講座教授。
