原位合成钛基复合材料的高温力学性能

Mechanical Properties of in situ Synthesized Titanium Matrix Composites at Elevated Temperatures

利用钛与B4C反应经普通的熔铸工艺制备了原位合成TiB和TiC增强的钛基复合材料。研究了原位合成钛基复合材料的高温力学性能和断裂机理。结果表明:随着温度的升高,其抗拉强度降低,伸长率提高。但与基体钛合金比较,由于原位合成增强体非常稳定,能有效地强化基体合金,明显提高了复合材料的高温抗拉强度。拉伸断裂机理与温度有关,室温时,增强体断裂是材料失效的主要原因;而随着温度的提高,增强体与基体合金界面脱粘成为材料失效的主要原因。

TiB and TiC reinforced titanium matrix composites were produced by common casting technique utilizing the reaction between titanium and B_4C. The mechanical properties and fracture mechanism of in situ synthesized titanium matrix composites were investigated at elevated temperatures. As temperature increases, the ultimate tensile strength decreases and ductility increases. Compared with matrix alloy, ultimate tensile strength improves obviously because the in situ synthesized reinforcements are very stable at elevated temperatures and can strengthen the matrix alloy effectively. The fracture mechanisms are related to temperature. The composites fail during tensile at room temperature due to the fracture of reinforcements. When temperature increases, the debonding between reinforcements and the matrix alloy becomes the main reason that makes composites fail.