(河南工程學(xué)院 機械工程學(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 ℃)熔點相差1597 ℃，為Hf-Sb二元相圖的測定帶來極大困難。本研究采用螺紋密封在室溫下制成固-液Hf-Sb二元擴散偶，在750~950 ℃五個溫度點恒溫退火14 d，獲得了五組擴散偶樣品，并對其進行了相平衡組織分析和成分測定。結(jié)果表明：經(jīng)電子探針組織觀察和成分分析，發(fā)現(xiàn)了嚴格計量比化合物HfSb2、有溶解度范圍的(HfSb)和固溶體相(Hf)三個平衡相，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互溶范圍有擴大趨勢；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
