摘要
冷坩埚定向凝固技术基于材料电磁加工原理,将合金连续熔化、电磁约束成形和连续凝固过程统一,避免模壳法定向凝固造成的合金熔体污染,是TiAl等高活性合金高纯净定向凝固的重要方法之一。报告了TiAl基合金冷坩埚定向凝固技术的研究结果,建立了电磁场、温度场与电磁冷坩埚系统主要参数之间的规律性关系。通过改变冷坩埚的横截面形状,初步制备出具有定向凝固组织的TiAl基合金圆、方和扁锭,研究结果表明该方法不但适合于Ti-Al二元合金,而且施与多元多相TiAl基合金也是可行的。通过对成分和组织的控制,所研究的TiAl基合金定向凝固试样的室温拉伸塑性最高达到1.5%左右。最后指出将该方法应用于耐高温的轻质高Nb含量的γ-TiAlNb合金的定向凝固是未来的发展趋势。
On basis of electromagnetic processing principle of materials, directional solidification technology based on electromagnetic cold crucible integrates the inductive melting into electromagnetic continuous casting using a water-cooled copper crucible device is investigated. It has been with much flexibility to perform directional solidification of TiAl avoiding contaminations by the present method compared to a traditional Bridgeman method. By systematic experiments and analysis on the behavior of the electromagnetic and temperature field within cold crucible and their coupling effect, a semi quantitative relationship between temperature, electromagnetic intensity and unit parameters of crucible was set up. Billets with multiple cross-sections of round and square as well as near-rectangular were solidified successfully into unidirectional structures for Ti-Al binary alloys, in which by controlling the compositions and modifying the microstructures it revealed that the method is available for TiAl-based alloy in muhiple composition and phases effectively. Finally, tensile testing results show that a tensile elongation of about 1.5% can be attained for as-DS samples. This means, due to the improvement of castings quality, enhancing its application for light-weight high-Nb containing γ-TiAlNb are with great prospective in the future.
出处
《中国材料进展》
CAS
CSCD
2010年第2期14-23,共10页
Materials China
基金
国家自然科学基金资助项目(50671032)
教育部"新世纪优秀人才支持计划"资助项目(NCET-08-0164)
关键词
TIAL基合金
冷坩埚
定向凝固
电磁场
TiAl-based intermetallics
cold crucible
directional solidification
electromagnetic field
