【摘要】 通过差示扫描量热法,设定升温速率为10 K/min,确定了铜基块体非晶合金Cu_47.5Zr_47.5-xAl₅Hf_x（x=0,9.5）的玻璃转变温度Tg为712～722 K,晶化温度Tx为747～766 K。结果表明,通过退火处理可获得铜基非晶合金或非晶-纳米晶复合材料。退火温度和退火时间影响组织结构和显微硬度。当退火温度高于Tg时,随着退火温度的升高以及退火时间的延长,显微硬度和结晶度逐渐增加然后趋于平缓。通过浸泡法和动电位极化法研究了铸态试样以及不同条件下退火后试样在3.5%（质量分数） NaCl溶液中的腐蚀行为。结果表明,Cu_47.5Zr_47.5-xAl₅Hf_x（x=0,9.5）试样在3.5%NaCl溶液中发生点蚀。与铸态试样相比,在623 K （即低于Tg）或773 K（即略高于Tx）退火30 min试样的自腐蚀电位升高,腐蚀电流密度略微增加,耐蚀性变化不大。在923 K （即远高于Tx）退火30 min后试样的自腐蚀电位显著降低,腐蚀电流密度变化不大,耐腐蚀性变差。Hf含量对耐腐蚀性的影响较小。更多还原

【Abstract】 Using differential scanning calorimetry（DSC） with heating rate of 10 K/min, the glass transition temperature Tgand the crystallization temperature Txof the Cu-based bulk metallic glasses（BMGs）Cu_47.5Zr_47.5-xAl₅Hf_x（x=0, 9.5） were determined to be 712～722 K and 747～766 K, respectively. X-ray diffraction（XRD） analysis confirmed that Cu-based metallic glass or metallic glass-nanocrystalline composites could be obtained throu-gh annealing. The microstructure and microhardness were affected by the annealing temperature and time. When the annealing temperature was above Tg, with the increase of annealing temperature and time, the crystallinity and the microhardness gradually increased and then leveled off. Immersion tests and potentiodynamic polarization tests were carried out to investigate the corrosion behavior of the as-cast and annealed samples in 3.5% NaCl solution. Pitting was observed on the Cu_47.5Zr_47.5-xAl₅Hf_x（x=0, 9.5） samples after immersion in 3.5% NaCl solution. Compared with the as-cast samples, the samples anneal-ed at 623 K（i.e. below Tg） or at 773 K（i.e. slightly above Tx） exhibited higher corrosion potential and slightly larger corrosion current density, indicating the similar corrosion resistance of them. The samples annealed at 923 K（i.e. much higher than Tx） for 30 min exhibited much lower corrosion potential and similar corrosion current density, indicating their poorer corrosion resistance. Hf content showed minor effect on the corrosion resistance.更多还原