中文摘要：

采用放电等离子烧结技术制备了全致密镝纳米晶块体材料,研究晶粒尺寸对其结构和磁性的影响。显微组织分析发现,在573K和773K的烧结条件下,材料的平均晶粒尺寸分别为10nm和100nm左右,晶体结构分析发现,镝纳米晶块体是与原始粗晶镝一样的密排六方结构晶体,磁性能测试结果表明,随着平均晶粒尺寸的下降,样品的奈尔温度（T_N）逐渐降低,而居里温度（T_C）则先降低后升高,在5K温度和9T磁场下,平均晶粒尺寸10nm的镝块体材料比粗晶镝的磁化强度降低了3.35%,矫顽力则增加了3倍。

英文摘要：

A full dense nanocrystalline Dy bulk materials was prepared by spark plasma sintering method. The structure and magnetic properties of the samples were studied. Microstructure analysis shows that the average grain sizes of Dy samples sintered at 573 K and 773 K are 10 and 100 nm, respectively. Crystal structure analysis indicates nanocrys- talline Dy bulk have close-packed hexagonal structure same as the original coarse-grained dysprosium crystal structure. Magnetic measurement displays that with the reduction of grain size, the Neel point gradually decreases, while the Curie point decreases flint, then increases again., The magnetization of nanocrystalline Dy bulk materials with average grain size about 10 nm was decreased by 3.35%, and the coercive force was increased by three times compared with those of coarse-grained bulk Dy sample under 5K and 9 T.