Lamellar spacing and mechanical property of undercooled Ti-45Al-2Cr-2Nb alloy

作者：Liu YC^*

来源：Materials Letters, 2003, 57(15): 2262-2266.

DOI：10.1016/S0167-577X(02)01207-7

• titanium alloy
• mechanical properties
• rapid solidification processing
• lamellar structures
• undercooling

Cyclic superheating technology was adopted effectively to undercool a Ti-45Al-2Cr-2Nb alloy melt in a containerless electromagnetic levitation apparatus. The maximum undercooling of the melt achieved was up to 252 K and phase alpha was detected as the primary phase in all the undercooled samples. TEM, SEM and optical microscopy techniques were used to investigate the microstructure and identify the phase composition. The arc-melted microstructure of the alloy was composed of the lamellae (alpha(2) + gamma) and the retained high temperature phase a, but it turned into a fully lamellar structure (alpha(2) + gamma) after homogenization at 1273 K for 80 h. The variance of lamellar spacing under different undercoolings was detected, and the strengthening effect of the fine lamellar microstructure on the hardness of the undercooled samples was evaluated. The minimum lamellar spacing of the alloy undercooled by 171 K is 134 nm with a Vickers hardness of 430.

• 出版日期2003-4
• 单位中国科学院金属研究所