氧化锆改性镁基复相材料热膨胀行为研究

Study on thermal expansion of ZrO modified Mg matrix composite

为了研究氧化锆对镁基复相材料热膨胀行为的影响,通过实验考察了氧化锆掺量对镁基复相材料热膨胀率、膨胀系数和受热后物理力学性能指标和热稳定性的影响,提出最佳的氧化锆掺量。结果表明:当温度超过1100℃时,镁基复相材料会发生明显的热膨胀,直至温度为1300℃时,膨胀率保持稳定;随着氧化锆掺量的增多,膨胀率和膨胀系数逐渐减小,当氧化锆掺量超过6%时,膨胀率和膨胀系数的变化幅度较小。氧化锆的加入会降低试样受热后的体积密度,同时提高试样受热后的抗折强度和显气孔率。随着氧化锆掺量的增多,镁基材料受热后的耐压强度和耐压强度保留率都呈现先增大后减小的变化规律,当氧化锆掺量为6%时,两者出现最大值,此时镁基材料具有最佳的热稳定性。综合考虑,镁基复相材料中氧化锆的最佳掺量应为6%。

In order to study the effect of ZrO2 on thermal expansion behavior of Mg matrix composites,the effect of zirconia content on the expansion rate,expansion coefficient and physical and mechanical properties and thermal stability of Mg matrix composites were studied.The results showed that when the temperature exceeded 1100℃,thermal expansion of Mg matrix material will occur,until the temperature was 1300℃,the expansion rate remained stable;With the increase of the amount of ZrO2,the expansion and expansion coefficient decreased.when the content of ZrO2 exceeded 6%,the change of expansion and expansion coefficient was smaller.The addition of ZrO2 will reduce the volume density after heating,and improved the flexural strength and apparent of the sample after heating.With the increase of the amount of ZrO2,the compressive strength and compressive strength retention rate of the Mg materials increased first and then decreased.when the content of ZrO2 was 6%,the maximum value of both,the Mg materials had the best thermal stability.Comprehensive consideration,the optimal content of ZrO2 in Mg matrix should be 6%.