An investigation of electronic property and high pressure phase stability of SmN has been conducted using first principles calculations based on density functional theory. The elec- tronic properties of Stun show a striking feature of a half metal, the majority-spin electrons are metallic and the minority-spin electrons are semiconducting. It was found that Stun undergoes a pressure-induced phase transition from NaCl-type （B1） to CsCl-type structure （B2） at 117 GPa. The elastic constants of Stun satisfy Born conditions at ambient pressure, indicating that B1 phase of SmN is mechanically stable at 0 GPa. The result of phonon spectra shows that B1 structure is dynamically stable at ambient pressure, which agrees with the conclusion derived from the elastic constants.
借助于扫描电镜,透射电镜研究了淬火T8A钢试样在170℃和400℃进行电场(4 k V/cm)与非电场回火2 h后的组织形貌,并对不同状态的试样进行了力学性能测试和冲击断口扫描观察。结果表明,电场与非电场回火试样的SEM形貌没有明显变化;400℃电场回火后TEM形貌中的碳化物与非电场TEM形貌中碳化物相比有明显球化的趋势,说明电场促进了回火进程;电场回火降低了试样的硬度值;与相应的非电场回火试样相比,400℃电场回火后,T8A钢的冲击吸收能量降低了27%,但170℃回火后,T8A钢试样冲击吸收能量提高了14%。
