环形薄壁Al-UO2弥散芯块的制备工艺

Fabrication Processes of Annular and Thin-walled Al-UO2 Dispersion Pellet

  • 摘要: 本文研究了环形薄壁Al-20%UO2弥散芯块的热压烧结和无压烧结工艺,分析了芯块的性能。研究发现:真空热压烧结弥散芯块的密度较低,且易出现开裂问题;真空无压烧结能制备合格的Al-20%UO2弥散芯块。对Al粉进行PVA湿法造粒,再与UO2粉末进行两步均匀混合,在550 MPa成型,Al-20%UO2压块的成型相对密度达93.45%,外径和内径的弹性后效分别为0.455%和0.194%。在490 ℃、4×10-2Pa真空无压烧结1 h,Al-20%UO2弥散芯块的烧结相对密度达94.54%;外径为(53.230±0.006) mm,膨胀率为0.415%;内径为(45.506±0.017) mm,膨胀率为0.278%。芯块不经研磨加工,可直接装管密封制成靶件。

     

    Abstract: The hot-press and free pressure sintering processes of the annular and thin-walled Al-20%UO2 dispersion pellets and their properties were studied. The vacuum free pressure sintering can produce good pellet, but the pellets produced by vacuum hot-press sintering may easily encounter the problems of low density and cracks. The granulation of Al powders by PVA solution method and two-step mixing process with UO2 powders were used to fabricate the green body of Al-20%UO2 with density of 93.45%TD at 550 MPa, and it’s outside diameter increases 0.455% and inside diameter increases 0.194% compared to diehole size. The Al-20%UO2 dispersion pellet was sintered by vacuum free pressure process at 490 ℃ and 4×10-2 Pa for 1 h with density of 94.54%TD, and outside diameter of (53.230±0.006) mm with swelling rate of 0.415%, and inside diameter of (45.506±0.017) mm with swelling rate of 0.278%. These pellets can be loaded into clad tube directly and sealed to assemble target without grinding.

     

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