2种轧制温度下BT25钛合金棒材组织与性能

Properties and Microstructure of BT25 Titanium Alloy Bars Processed at Different Rolled Temperatures

研究了980℃和950℃2种温度轧制的BT25钛合金棒材的室、高温拉伸性能、热稳定性能以及持久性能。研究结果表明,所研究的2种温度下得到的轧制棒材的性能均满足用户提出的标准要求。它们的高温拉伸性能、冲击韧性相当,980℃轧制棒材的室温拉伸性能优于950℃轧制棒材,但后者的热稳定性优于前者,550℃热暴露100 h后,后者塑性降低程度较小。BT25钛合金棒材组织比较均匀,均为初生α相和条状β转变组织构成的双态组织,且变形温度较低时,组织较细小,合金的综合性能较高,尤其是热稳定性能较好。

Tensile properties both at ambient and high temperature, thermal stabilities and duration time for BT25 tita- nium alloy bars rolled at 980 ℃ and 950 ℃, respectively were determined. The results indicate that the properties for all the bars can meet the requirements for the corresponding standards which put forward by the users. Tensile proper- ties at 500℃ and 550℃and impact toughness for the rolled bars are almost the same. Tensile properties at ambient temperature for bars rolled at 980 ℃ are superior to that of bars rolled at 950 ℃. Thermal stabilities for bars rolled at 950 ℃are superior to that of bars rolled at 980 ℃. and ductility decrease for bars rolled at 950 ℃ which have been exposed at 950 ℃ for 100 h is less than bars rolled at 980 ℃. Uniform bimodal microstructures can be found for the two kinds of bars rolled at 980 ℃and 950 ℃, respectively, which are composed of primary and strip-like transformed. The lower the deformation temperature, the finer the microstmctures and favorite comprehensive properties can be got, especially with good thermal stabilities.