采用锻态工业纯钛TA1标准拉伸试样,利用Gleeble-1500D热模拟试验机进行高温拉伸试验,研究其高温拉伸性能;并用SEM观察并分析工业纯钛拉伸试样断口形貌及其形成机制。结果表明:随温度升高,工业纯钛的屈服强度和抗拉强度分别从最初的83.7和94.8 MPa减小到19.3和29.6 MPa;伸长率增大,在950和1000℃时分别达到峰值36.3%和28%。在882.5℃相变转变温度以下,纯钛表现为以微孔聚集型剪切断裂为特征的韧性断裂,随温度的升高,达到相变点882.5℃,纯钛发生同素异构转变,并伴随着塑性提高,以准解理方式断裂。
The high-temperature tensile tests of the forged commercially pure titanium TA1 were carried out to study its high-temperature tensile properties by Gleeble-1500 D thermal simulated test machine. The tensile properties at high temperatures were investigated. The relevant fracture morphologies and formation mechanism were analyzed by SEM. The result shows that, with the increase of temperature, the yield strength and tensile strength of CP titanium TA1 decrease from the original values of 83.7 and 94.8 MPa to 19.3 and 29.6 MPa, respectively. The ductility reaches the peak values of 36.3% and 28% at the temperatures of 950 and 1000 ℃, respectively. Below the phase transition temperature of 882.5 ℃, the ductile fracture failure occurs for the CP titanium in the form of microvoid coalescence shear fracturing. With the further increase of temperature, allotropy transformations occur, and the ductility increases, resulting in the quasi-cleavage fracture as the major failure mechanism.