Ni₄₇Ti₄₄Nb₉合金中各相的低温热容^①

来源期刊：中国有色金属学报1996年第2期

论文作者：杨冠军 郝士明

文章页码：104 - 107

关键词：Ni₄₇Ti₄₄Nb₉合金 热容 热弹性马氏体相变 绝热量热装置

Key words：Ni₄₇Ti₄₄Nb₉ alloy; heat ca pacity; thermoelastic martensitic transformation ;adiabtic calorimeter

摘    要：采用精密自动绝热量热装置测定了Ni₄₇Ti₄₄Nb₉和Nb₈₀Ti₁₄Ni₆合金60~350K温区的热容，并将热容实测值用最小二乘法进行了曲线拟合。在合金摩尔热容加和原则基础上，计算了Ni₄₇Ti₄₄Nb₉合金中TiNi基体相的热容。Ni₄₇Ti₄₄Nb₉合金在215-~260K范围内发生的相变是TiNi相的热弹性马氏体相变。相变起始温度(A_s)为222 K，相变终了温度(A_f)为255 K，相变焓△H= 411.9士2. 5J·mol^-1，相变熵△S= 1.76士0. 01J·K^-1·mol^-1。

Abstract: The heat capacities of Ni₄₇Ti₄₄Nb₉ and Nb₈₀Ti₁₄Ni₆ alloys in the temperature range from 60 to 350K were measured by means of an adiabatic calorimeter, and experimental data of heat capacity of Ni₄₇Ti₄₄Nb₉ alloy were fitted by the least square method. The heat capacity of TiNi phase in Ni₄₇Ti₄₄Nb₉ alloy was calculated on the basis of additivity of molar heat capacity. The transition peak between 215K and 260K was associated with the reverse thermoelastic martensitic transformation. Transformation start temperature, transformation finish temperature, transformation enthalpy and entropy were determined to be A_s=222 K,A_f=255 K,ΔH=411.9±2.5 Jmol^-1,ΔS=1.76±0.01JK^-1·mol^-1, respectively. Key words:Ni47Ti44Nb9alloy heat capacity thermoelastic martensitic transformation adiabtic calorimeter