研究了两相钛合金TC21关于两种不同微观组织(片状组织和网篮组织)的拉伸性能、断裂韧性和疲劳裂纹扩展性能。结果显示:片状组织相比网篮组织有相近的拉伸强度,但塑性较差;两者的韧性相差不大,但增韧机理不同;网篮组织在中低速扩展区的扩展速率和片状组织几乎相同,但在较高速扩展区显示略低的扩展速率;加载方向对两种组织的疲劳裂纹扩展速率基本无影响;和其他钛合金类似,TC21在Paris区存在转折。

Mechanical properties,including tensile property,fracture toughness and fatigue crack growth rates,have been investigated for two different microstructures of two-phase titanium alloys,TC21.It was found from tensile test results that the lamellar microstructure has almost the same tensile strength but inferior ductility property compared with the basketweave microstructure.Fracture toughness of these two microstructures was improved by different mechanisms.Large crack growth rates of basketweave microstructure were found nearly the same with lamellar microstructure at lowerΔK range,but slower at higher ΔK range.The load direction on specimens has little influence on crack propagation behavior for these two types of microstructures.Transitions occurred in the Paris regime of crack growth rate curve of TC21,which are smilar to some other titanium alloys.