(合肥工業(yè)大學 材料科學與工程學院 金屬液/固加工研究所，合肥 230009)
摘 要: 以Zr48Cu36Al8Ag8為研究對象，結(jié)合差示掃描量熱法和X射線衍射法，以電阻法探索高流變成型法對塊體非晶合金β弛豫及熱穩(wěn)定性的作用規(guī)律。升溫速率為10 K/min的驗證試驗表明，電阻法所標定樣品的β弛豫開始溫度Tβ、一次晶化開始溫度Tx-onset及其區(qū)間等特征參數(shù)均與差示掃描量熱法結(jié)果相吻合。這證明電阻法探索β弛豫及熱穩(wěn)定性的有效性。為進一步獲得更細致信息，以升溫速率1 K/min約化電阻率曲線揭示，高流變成型法成型后樣品的Tβ大幅提前，且β弛豫所致電阻率變化值Δρrel顯著增加，表明高流變成型法顯著增強該塊體非晶合金β弛豫強度；成型后Tx-onset滯后且晶化溫度區(qū)間ΔTx變寬，反映高流變成型法提高了該塊體非晶合金的熱穩(wěn)定性。這一結(jié)論得到不同溫度水淬樣品X射線衍射結(jié)果證實，盡管成型前后的最終晶化相并未改變。
關(guān)鍵字: 塊體非晶合金；高流變成型法；β弛豫；熱穩(wěn)定性
（Liquid/Solid Metal Processing Institute, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China）
Abstract:This work, combining with differential scanning calorimetry (DSC) and X-ray diffraction (XRD) methods, adopts the resistivity method to investigate the effects of HRRF on β relaxation and thermal stability of Zr48Cu36Al8Ag8 bulk metallic glass (BMG). The verification tests at a heating rate of 10 K/min show that, the characteristic parameters calibrated by the resistivity method, like β relaxation onset temperature Tβ, the first crystallization onset temperature Tx-onset and its related interval, are consistent with DSC results perfectly, which manifests the effectiveness of the resistivity method on exploring β relaxation and thermal stability of Zr48Cu36Al8Ag8 BMG. For more detailed information, the normalized resistivity curves at a heating rate of 1 K/min are obtained, which uncover a sharp Tβ advance and a significant increase in the resistivity change value Δρrel contributed by the β relaxation of the formed BMG, indicating an intensified β relaxation of the formed BMG; furthermore, obviously lagging Tx-onset and broadening ΔTx of the formed BMG evince significantly enhance thermal stability of the formed BMG, which gets further confirmation by XRD results of the water-quenched samples at different temperatures, despite the identical final crystallization phases of both as-cast and formed BMG samples.
Key words: bulk metallic glass; high rheological rate forming method; β relaxation; thermal stability
