The high dislocation density in some local areas of the dislocation sub-structures is the major factor which is responsible for the severe LCF damage and fatigue life reduction of Titanium alloy BT9.

• 非比例载荷下钛合金BT9中的局部高密度位错是其低周疲劳损伤程度加剧及寿命降低的主要因素。