The microstructure of an explosively compacted Nd-Fe-B permanent magnet（Nd-Fe-B） was investigated by means of TEM and XRD. It is shown that there are three kinds of phases: Nd2Fe14B matrix phase, O-rich phases and N...The microstructure of an explosively compacted Nd-Fe-B permanent magnet（Nd-Fe-B） was investigated by means of TEM and XRD. It is shown that there are three kinds of phases: Nd2Fe14B matrix phase, O-rich phases and Nd-rich phase with different structures and compositions in the magnet. The hard magnetic phase Nd2Fe14B is tetragonal, which lattice parameters are determined to be a=0.88 nm and c=1.22 nm. The O-rich phase locates at the grain boundaries and the triple junctions has fcc structure whose lattice parameter is a=0.559 nm. A dislocation is observed in this phase. It is also found that a large number of the block-shaped Nd-rich phases with hcp structure are embedded in the Nd2Fe14B matrix or at grain boundary. Their lattice parameters are determined to be a=0.395 nm and c=0.628 nm.展开更多
为探索不同温度下 B炸药易损性的响应特性，评价穿透深度和环境温度对 B炸药响应程度的影响，用12．7 mm 穿甲燃烧弹以850 m＆#183;s-1速度侵彻了 B炸药。研究了-40，25，70℃温度下 B 炸药的响应特性。用非线性有限元软件 ANSYS/LS-DYN...为探索不同温度下 B炸药易损性的响应特性，评价穿透深度和环境温度对 B炸药响应程度的影响，用12．7 mm 穿甲燃烧弹以850 m＆#183;s-1速度侵彻了 B炸药。研究了-40，25，70℃温度下 B 炸药的响应特性。用非线性有限元软件 ANSYS/LS-DYNA模拟了弹丸侵彻过程，研究了 B 炸药力学性能对易损性的影响。结果表明：在25℃条件下，B 炸药极限侵彻深度为200～250 mm。B炸药在-40，25，70℃条件下最高反应级别分别为爆燃、爆炸、爆燃反应。高温、低温环境抑制了B炸药对弹丸侵彻的反应程度。装药剪切模量下降可使 B炸药响应程度降低。展开更多
基金Project(50071035) supported by the National Natural Science Foundation of China Project(02ZE14054) supported bythe Natural Science Foundation of Shanghai China
文摘The microstructure of an explosively compacted Nd-Fe-B permanent magnet（Nd-Fe-B） was investigated by means of TEM and XRD. It is shown that there are three kinds of phases: Nd2Fe14B matrix phase, O-rich phases and Nd-rich phase with different structures and compositions in the magnet. The hard magnetic phase Nd2Fe14B is tetragonal, which lattice parameters are determined to be a=0.88 nm and c=1.22 nm. The O-rich phase locates at the grain boundaries and the triple junctions has fcc structure whose lattice parameter is a=0.559 nm. A dislocation is observed in this phase. It is also found that a large number of the block-shaped Nd-rich phases with hcp structure are embedded in the Nd2Fe14B matrix or at grain boundary. Their lattice parameters are determined to be a=0.395 nm and c=0.628 nm.
文摘为探索不同温度下 B炸药易损性的响应特性，评价穿透深度和环境温度对 B炸药响应程度的影响，用12．7 mm 穿甲燃烧弹以850 m＆#183;s-1速度侵彻了 B炸药。研究了-40，25，70℃温度下 B 炸药的响应特性。用非线性有限元软件 ANSYS/LS-DYNA模拟了弹丸侵彻过程，研究了 B 炸药力学性能对易损性的影响。结果表明：在25℃条件下，B 炸药极限侵彻深度为200～250 mm。B炸药在-40，25，70℃条件下最高反应级别分别为爆燃、爆炸、爆燃反应。高温、低温环境抑制了B炸药对弹丸侵彻的反应程度。装药剪切模量下降可使 B炸药响应程度降低。
