Mechanical response of the TiAl/steel brazed joint under impact load

Mesnager impact tests of TiAl base metal and TiAl/steel brazed joints were conducted at room temperature (293 K) and elevated temperature (623 K). Impact strength, impact energy, fracture path, and the behavior of the reaction phases were studied. For the room temperature test, average impact energy and strength of the joint are 71.9% and 84.2% of the TiAl base metal, respectively; which are 62.5% and 75.3% of TiAl base metal, respectively, at 623 K. Fracture path and crack propagation process analysis show, when subjected to the impact load, cracks germinate at the interface of Ag-based solid solution/AlCu₂Ti particles, grow up and propagate into the Al-Cu-Ti brittle reaction layers, then propagate into the TiAl base metal, and result in failure.