论文部分内容阅读
将Ti、Al混合粉以100℃/min的升温速率在400～980℃采用放电等离子方式进行烧结。通过XRD以及EPMA分析了烧结试样中的相和组织形貌,研究了Ti、Al混合粉在放电等离子烧结过程中的相变规律。结果表明,Ti、Al混合粉烧结中发生的相变符合Ti、Al粉体扩散反应的一般规律,即反应是由Al向Ti的扩散主导的。烧结过程可分为4个阶段:颗粒软化阶段、Al3Ti形成阶段、中间相生成阶段、最终产物生成及致密化阶段。在低于Al的熔点温度烧结时生成Al3Ti;Al消耗完之后,Al3Ti中的Al继续向Ti颗粒扩散,导致Al3Ti减少,并在界面上生成Ti2Al5、Al2Ti、TiAl及Ti3Al。在生成Al3Ti阶段,Al的熔化加快了反应速率。同时,适当施压可抑制Al的反致密化效果,得到致密度为98%的块体。
The Ti and Al mixed powders were sintered at 400 ~ 980 ℃ with a discharge plasma at a heating rate of 100 ℃ / min. The phase and microstructure of the sintered samples were analyzed by XRD and EPMA. The phase transformation of Ti and Al powders during spark plasma sintering was studied. The results show that the phase transformation during the sintering of Ti and Al powders follows the general rule of Ti and Al powder diffusion reactions that the reaction is dominated by the diffusion of Al to Ti. Sintering process can be divided into four phases: particle softening phase, Al3Ti formation phase, mesophase generation phase, the final product generation and densification phase. Al3Ti is formed when sintered at a temperature lower than the melting point of Al. After Al is depleted, Al in Al3Ti continues to diffuse into the Ti particles, resulting in reduction of Al3Ti and formation of Ti2Al5, Al2Ti, TiAl and Ti3Al at the interface. Melting of Al accelerates the reaction rate during Al3Ti generation. At the same time, appropriate pressure can inhibit the anti-densification effect of Al, resulting in a density of 98% of the block.