室温下TC11钛合金准静态拉伸力学性能实验研究

Experimental study on quasi-static tensile mechanical properties of TC11 titanium alloy at room temperature

针对典型航空材料TC11钛合金的拉伸性能,采用准静态拉伸实验对不同应变率条件下的TC11钛合金的应力-应变关系进行了研究,利用扫描电镜分析了其拉伸断口形貌。实验结果表明:TC11钛合金具有一定的应变率敏感性,抗拉强度和屈服强度均会受到应变率的影响;准静态拉伸时TC11钛合金试样出现了颈缩现象,试样截面形状为杯锥状,试样断口存在光滑的剪切唇区和灰色的纤维区,其断裂属于韧性断裂,但是其韧性较差;TC11钛合金拉伸断口形貌主要为大小不一的韧窝,随着应变率的增大,试样拉伸断口韧窝的大小和深度均变小,同时出现了少量的撕裂棱和准解理面,试样的断裂机制为以韧性断裂为主和伴有准解理断裂。因此,在准静态拉伸条件下,TC11钛合金的力学行为与应变率有关。

According to the tensile properties of typical aerospace material TC11 titanium alloy,the stress-strain relationship is studied using the quasi-static tensile test at different strain rates,and the tensile fracture morphology is analyzed with SEM.The experimental results show that TC11 titanium alloy has certain strain rate sensitivity,and both tensile strength and yield strength are affected by strain rate.During quasi-static tension test,TC11 titanium alloy specimen has the phenomenon of neck shrinkage.The section of the specimen is cuppy,and there is smooth shear lip zone and grey fiber area in the sample fracture.The fracture of the samples belongs to ductile fracture,but its toughness is poor.The tensile fracture morphology of TC11 titanium alloy is mainly the dimple with different sizes,but with the increase of strain rate,the size and the depth of dimple at the tensile fracture are smaller,and the fracture surface produces a small number of tearing edges and quasi-cleavage plane,andthe fracture mechanism of the specimen is mainly ductile fracture and quasi-cleavage fracture.Therefore,the mechanical behavior of TC11 titanium alloy is related to strain rate under quasi-static tensile condition.