Solidification characteristics of high Nb-containing γ-TiAl-based alloys with different aluminum contents  

作　　者：Yi Liu Rui Hu Hong-Chao Kou Jun Wang Tie-Bang Zhang Jin-Shan Li Ji Zhang 

机构地区：[1]The State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University [2]Institute of High Temperature Materials, China Iron and Steel Research Institute Group

出　　处：《Rare Metals》2015年第6期381-386,共6页稀有金属（英文版）

基　　金：financially supported by the National Basic Research Program of China(No.2011CB605503);the Program of Introducing Talents of Discipline to Universities(No.B08040)

摘　　要：The effect of A1 content on the microstructure and solidification characteristics of Ti-A1-Nb-V-Cr alloys in as-cast and isothermally treated states was investigated using X-ray diffraction （XRD）, scanning electron microscopy （SEM） equipped with energy dispersive spectroscope （EDS）, and transmission electron microscopy （TEM）. The typical solidification characteristics are due to the joint influence of both the crystal temperature range and the solidification path. The wide crystallization temperature range contributes to obtaining coarse dendrites in the as-cast Ti47A17Nb2.5V1.0Cr （at%） alloy solidifying through the peritectic reaction. The β-solidifying Ti46A17Nb2.5V1.0Cr （at%） alloy with the narrow crystallization temperature range is attributed to the formation of a homogeneous finegrained microstructure. However, the crystallization temperature range of Ti48A17Nb2.5V1.0Cr （at%） alloy is equivalent to that of Ti46A17Nb2.5V1.0Cr alloy, but it is solidified by peritectic reaction, leading to the formation of finer dendrites.The effect of A1 content on the microstructure and solidification characteristics of Ti-A1-Nb-V-Cr alloys in as-cast and isothermally treated states was investigated using X-ray diffraction （XRD）, scanning electron microscopy （SEM） equipped with energy dispersive spectroscope （EDS）, and transmission electron microscopy （TEM）. The typical solidification characteristics are due to the joint influence of both the crystal temperature range and the solidification path. The wide crystallization temperature range contributes to obtaining coarse dendrites in the as-cast Ti47A17Nb2.5V1.0Cr （at%） alloy solidifying through the peritectic reaction. The β-solidifying Ti46A17Nb2.5V1.0Cr （at%） alloy with the narrow crystallization temperature range is attributed to the formation of a homogeneous finegrained microstructure. However, the crystallization temperature range of Ti48A17Nb2.5V1.0Cr （at%） alloy is equivalent to that of Ti46A17Nb2.5V1.0Cr alloy, but it is solidified by peritectic reaction, leading to the formation of finer dendrites.

关 键 词：Titanium aluminide Crystal temperaturerange Peritectic reaction Dendrite morphology Al-equivalent 

分 类 号：TG146.23[一般工业技术—材料科学与工程]