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将Ti、Al单质粉在行星球磨机中以15∶1的球粉比、180 r/min的转速球磨20 h。将所得的球磨粉以100℃/min的升温速率在440~980℃以及40 MPa的压力下以放电等离子法烧结。通过XRD以及EPMA分析了烧结试样中的相及组织形貌,研究了Ti、Al球磨粉在放电等离子烧结过程中的相变规律,并将其与Ti、Al混合粉的相变规律进行对比。结果表明,Ti、Al球磨粉烧结的相变过程可分为4个阶段:颗粒软化阶段、TiAl3生成阶段、中间相生成阶段以及最终产物生成阶段。机械球磨过程细化了粉体颗粒,并发生点阵畸变,导致球磨粉的烧结过程与混合粉相比,具有反应温度低、反应快、烧结容易实现致密化的特点。由于烧结过程中没有出现液相,且高温时晶粒长大迅速,球磨粉的烧结可以由室温起施压,并需在900℃以下温度进行烧结。
The Ti and Al powders were ball milled for 20 h in a planetary ball mill at a ball-to-powder ratio of 15: 1 and a rotation speed of 180 r / min. The resulting ball mill powder was sintered by a discharge plasma method at a heating rate of 100 ° C./min at 440 to 980 ° C. and a pressure of 40 MPa. The phase and microstructure of the sintered samples were analyzed by XRD and EPMA. The phase transformations of Ti and Al powders during spark plasma sintering were studied. The phase transitions of Ti and Al powders were compared with that of Ti and Al powders . The results show that the phase transformation process of Ti and Al ball milling sintering can be divided into four stages: particle softening stage, TiAl3 formation stage, mesophase formation stage and final product formation stage. Mechanical ball milling process refined the powder particles, and lattice distortion, resulting in the process of milling powder with mixed powder, with a low reaction temperature, fast reaction, easy to achieve the characteristics of sintering densification. As the liquid phase does not appear during sintering and the grains grow rapidly at high temperatures, the sintering of the ball mill powder can be started from room temperature and sintered at a temperature below 900 ° C.