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采用扩散偶法研究了原位烧结过程中AlB2的形成过程及成相控制环节。扩散实验表明:铝的扩散能力远大于硼的扩散能力,Al-B体系成相主要是通过Al向B扩散实现的;Al-B可以在固-固态和液-固态下发生反应生成AlB2相;固-固态下,相互接触的Al和B通过原子间相互扩散在接触处形成固溶活化区,AlB2相便在该活化区内形成。固-固态下控制Al-B反应发生的因素是Al原子穿越反应产物的扩散能力;液-固态下控制Al-B发生反应的因素是熔融态Al对固相产物的润湿性。
The formation process and phase control of AlB2 during in-situ sintering were studied by using diffusion-even method. The diffusion experiments show that the diffusion ability of aluminum is much larger than that of boron. Al-B phase is mainly diffused by Al to B; Al-B phase can react in solid-solid state and liquid-solid state to form AlB2 phase; In the solid-solid state, Al and B, which are in contact with each other, form a solid solution activation zone at the contact through inter-atomic diffusion and the AlB2 phase is formed in the activation zone. The factors that control Al-B reaction in solid-solid state are the diffusivity of Al atoms crossing the reaction product. The factor that controls the reaction of Al-B in liquid-solid state is the wettability of Al in solid phase.