Determination of Phase Transformation for TC21 Ti-Alloy by Dilatometry Method

作     者：Ramadan N. Elshaer Khaled M. Ibrahim Azza F. Barakat Ahmed I. Farahat Reham R. Abbas 

作者机构：Tabbin Institute for Metallurgical Studies Cairo Egypt Central Metallurgical R & D Institute Cairo Egypt Faculty of Engineering Helwan University Cairo Egypt Faculty of Engineering Suez University Suez Egypt 

出 版 物：《Open Journal of Metal》 (金属学报（美国）)

年 卷 期：2019年第9卷第1期

页      面：1-10页

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

主　　题：TC21 Ti-Alloy Phase Transformation Dilatometry Heating Cooling 

摘      要：The α + β ? β phase transformation kinetics of TC21 Ti-alloy during continuous heating and cooling were studied using a dilatometric technique. Dilatometric heating curve exhibited that two characteristic reflection points can be observed with increasing the heating temperature. Ts referred to the initial transformation temperature of α + β → β and Tf referred to the final transformation temperature of α + β → β. Ts was reported at 720°C, whereas the corresponding Tf was obtained at 950°C. The initial and final transforming temperatures by the first derivative curve were reported at 730°C and 955°C, respectively, which are close to the values obtained in the dilatometric heating curve. Dilatometric cooling curve showed that the starting temperature of β → β + α phase transformation was 880°C;however, the corresponding finishing temperature was 670°C. The starting and finishing temperatures using the first derivative curve were obtained at 665°C and 885°C, respectively. The first derivative for the studied dilatometric heating and cooling curves showed that the starting and finishing temperatures of α + β ? β phase transformation were more accurate and objective. Results show the α + β → β transformation heating curve exhibits a typical S-shaped pattern.