Effect of the Pulling Velocity of Directional Solidification on Thermal Conductivity of Mg-Ag-Zn Alloys

Specimens of as-cast Mg-1Ag-Zn, Mg-3Ag-Zn and Mg-5Ag-Zn alloys were fabricated, and then the specimens' thermal conductivity was calculated. With the increase of Ag content, the thermal conductivity of as-cast alloys decreases significantly. After that, directionally solidified specimens of the above mentioned as-cast Mg-Ag-Zn alloys were made at three different pulling velocities: V=25 μm/s, V=50 μm/s, V=75 μm/s, and then their thermal conductivity was calculated again. The results show that with the increase of the pulling velocity, the thermal conductivity of alloys decreases significantly. Variations in the solute content and the pulling velocities are believed to play important roles in the thermal conductivity of Mg-Ag-Zn alloys. Since these two factors can strengthen the electron's scattering process, reduce their free path, and thereby reduce the alloys' thermal conductivity.