Al-34%Mg-6%Zn和Al-28%Mg-14%Zn合金的热分析研究

利用差示扫描量热仪(DSC)和H-90型膨胀仪,对潜热储能材料A l-34%Mg-6%Zn和A l-28%Mg-14%Zn合金的热物性参数进行了测定,如固、液态时的比热容,30~500℃间的质量密度,熔化温度和熔化潜热等.测试结果表明,两种合金的熔化温度和熔化潜热分别为454℃、447℃和314.4 kJ/kg、303.2 kJ/kg.从室温加热到熔化温度时,两种合金的密度分别减少1.05%和1.09%.在相变之前,两种合金的比热容随温度的升高而增大,在445℃时,分别为1 368.5 J.kg-1.k-1、1 203.6 J.kg-1.K-1.在相变过程中,由于熔化潜热的原因,合金的比热容变化很大.从理论计算值的比较和误差分析来看,上述热物性参数的测试结果是可信的.本文还对合金组元和相对热物性参数的影响进行了讨论.

Thermal Analytical Investigations of Al-34% Mg-6% Zn and Al-28%Mg-14%Zn Alloys

The following thermo-physical properties are determined for Al-34%Mg-6%Zn（in wt.%） and Al-28%Mg-14%Zn alloys used for thermal energy storage applications,such as the specific heat capacity including solid and liquid state;the mass density in the temperature range 30～500℃;the melting temperature and the latent heat of fusion.The properties are measured by differential scanning calorimetry（DSC） and H-90 type dilatometer.The test results show that the melting temperature and latent heat of fusion for the two alloys are 454℃,447℃ and 314.4kJ/kg,303.2kJ/kg,respectively.Their density heated from room temperature to melting temperature are decreased by（1.05%）,（1.09%）,respectively.Their specific heat capacity are growing with the temperature increasing before the beginning of phase change,and are 1368.5 J·kg-1·K-1,1203.6 J·kg-1·K-1 at 445℃,respectively.The change of specific heat capacity are great due to the existing of latent heat of fusion during the phase transformation process.The measured results mentioned above are credible from the points of view of comparing with the value of theory calculation and error analysis of data.The mechanism that the effect of alloy compositions and phases on these properties is discussed in this paper.