(河南工程學(xué)院 機(jī)械工程學(xué)院，鄭州 451191)
摘 要: Hf-Sb二元系作為熱電材料Half-Heusler合金的重要組元，因Hf(2227 ℃)與Sb(630 ℃)熔點(diǎn)相差1597 ℃，為Hf-Sb二元相圖的測(cè)定帶來極大困難。本研究采用螺紋密封在室溫下制成固-液Hf-Sb二元擴(kuò)散偶，在750~950 ℃五個(gè)溫度點(diǎn)恒溫退火14 d，獲得了五組擴(kuò)散偶樣品，并對(duì)其進(jìn)行了相平衡組織分析和成分測(cè)定。結(jié)果表明：經(jīng)電子探針組織觀察和成分分析，發(fā)現(xiàn)了嚴(yán)格計(jì)量比化合物HfSb2、有溶解度范圍的(HfSb)和固溶體相(Hf)三個(gè)平衡相，獲得了相應(yīng)溫度下的Hf-Sb二元系的相平衡關(guān)系和共軛平衡成分。其中，化合物(HfSb)成分范圍為48.41%~52.23% Sb，隨著溫度的增高，Hf-Sb互溶范圍有擴(kuò)大趨勢(shì)；化合物HfSb2高溫下不穩(wěn)定，在900 ℃以上發(fā)生偏晶分解。
關(guān)鍵字: Hf-Sb二元系；擴(kuò)散偶；相平衡；相圖
（School of Mechanical Engineering, Henan University of Engineering, Zhengzhou 451191, China）
Abstract:As an important component of thermoelectric Half-Heusler alloys, the melting point difference between Hf(2227 ℃) and Sb(630 ℃) is 1597 ℃, which makes it very difficult to build the Hf-Sb binary phase diagram. In this work, the solid-liquid Hf-Sb binary diffusion couples were fabricated by screw seal at room temperature. After annealing at five temperature points from 750 ℃ to 950 ℃ for 14 d, five groups of diffusion couple samples were obtained, and their phase equilibrium structure and composition were analyzed. The results show that three equilibrium phases, strictly stoichiometric compound HfSb2, (HfSb) with solubility range and solid solution (Hf), are found, the phase equilibrium relationship and the conjugate equilibrium compositions of Hf-Sb binary system at corresponding temperature were obtained by electron probe microanalysis (EPMA). The composition range of (HfSb) compound is 48.41%-52.23% Sb, the mutual solubility range of Hf-Sb tends to expand with the increase of temperature. The compound HfSb2 is unstable at high temperature and undergo monotectic decomposition above 900 ℃.
Key words: Hf-Sb binary system; diffusion couple; phase equilibrium; phase diagram
