Deformability and microstructure transformation of PM TiAl alloy prepared by pseudo-HIP technology

• Published in: Transactions of Nonferrous Metals Society of China 2010-04, Vol.20 (4), p.547-552
• Main Author: 张伟 刘咏 刘彬 李慧中 唐蓓
• Format: Article
• Language: English
• Subjects: Alloy powders; Compressing; Cracks; deformability; Deformation; Dislocation mobility; Intermetallic compounds; Intermetallics; Microstructure; powder metallurgy; pseudo-hot isostatic pressing; Titanium aluminides; Titanium base alloys
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(09)60176-X

Microstructures and deformation properties of Ti-46Al-（Cr,Nb,W,B）alloy consolidated by pseudo-HIP technology were investigated.The results show that the pseudo-HIP temperature has a significant effect on microstructures.When the sintering temperature is 1 100℃,the microstructure of as-pseudo-HIPped alloy is similar to that of the prealloyed powder and the interfaces of these powder particles are still discernible,but a nearγmicrostructure appears in particles.Increasing the pressing temperature to 1 200℃develops successfully a homogeneous and fine-grained duplex microstructure.A typically fully lamellar microstructure with residualβphase is developed at 1 300℃.The compact exhibits excellent deformation properties at elevated temperatures. When the compression temperature is higher than 1 100℃,high quality products without cracks can be obtained even if the engineering compression strain is up to 0.8 at strain rates of 10-2-10-3s-1.It can be established that the mechanical twinning and matrix deformation due to ordinary dislocation slip/climb contribute to the whole hot deformation.