【摘要】 利用脉冲小孔喷射法在混合50%Ar+50%He(体积分数)惰性气氛下制备出了粒径可控的均匀球形[(Fe0.5Co0.5)0.75B0.2Si0.05]96Nb4金属玻璃微粒子,通过XRD、DSC以及TEM对所获得的粒子进行检测分析。结果表明,这些微粒子均具有粒径均匀和圆球度高等优良特点。随着粒径减小,微粒子的微观结构从全结晶相逐渐向混合相,并最终向全金属玻璃相转变。制备的粒子内部为全玻璃相的临界尺寸大致为515μm。通过冷却速率的计算,得到全玻璃相微粒子的临界冷却速率为800～1100 K/s。该速率与环境气氛的改变无关,并且该计算值低于同成分的大块金属玻璃合金TTT曲线的测量值。更多还原

【Abstract】 [(Fe0.5Co0.5)0.75B0.2Si0.05]96Nb4 metallic glass alloy particles were prepared with narrow size distribution and high sphericity in a mixed inter gas atmosphere 50%Ar +50%He(volume fraction) by pulsated orifice ejection method.The analysis of the obtained particles was carried out by X-ray diffraction(XRD),differential scanning calorimetry(DSC) and transmission electron microscope(TEM).The results show that the phase transitions of particles from the fully crystalline phase to the mixed phase which is consisted of the glassy phase and the crystalline phase to the fully glassy phase occurs as the particle diameter decreases.The particles obtained in the fully glassy phase have a diameter of less than 515 μm.Critical cooling rate for fully glassy phase is estimated to be in the range of 800～1100 K/s.No changes of the critical cooling rate occur in argon or helium atmosphere.Critical cooling rate measured in this method is definitely lower than that measured by time-temperature transformation diagram of bulk metallic alloy.更多还原