TiC<sub>p</sub>/7075Al基復合材料半固態坯料二次加熱組織

TiC_p/7075Al基復合材料半固態坯料二次加熱組織

摘要: 利用掃描電鏡(SEM)、透射電鏡(TEM)和示差掃描量熱法(DSC)研究了4.4%TiC_p/7075Al基復合材料的二次加熱組織演變規律及其影響因素.結果表明:4.4%TiC_p/7075Al基復合材料的最佳二次加熱工藝參數是加熱溫度為590~610℃,保溫時間為10~20min;4.4%TiC_p/7075Al基復合材料在二次加熱過程中具有較高的穩定性,隨溫度的升高和保溫時間的延長,球形晶粒尺寸增加較小;4.4%TiC_p/7075Al基復合材料在600℃時的晶粒粗化速率常數為118.96μm³·s^-1,遠小于7075基體合金的晶粒粗化速率常數311.7μm³·s^-1,更加適宜于半固態觸變成形.

Abstract: The reheated microstructures and influencing factors of semi-solid ingots of 4.4% TiC_p/7075 composites were investigated by SEM, TEM and DSC. The results show that the optimal remehed parameters of 4.4% TiC_p/7075 composites are the remolded temperature of 590 to 610℃ and the holding time of 10 to 20 min. 4.4% TiC_p/7075 composites are of high stability during the remelting process and the size of spherical grains can hardly increase with the increase of temperature and holding time. The coarsening velocity of grains in 4.4% TiC_p/7075 is 118.96μm³·s^-1, which is less than 311.7 μm³· s^-1 for 7075 matrix alloy, and more suitable for semi-solid thixoforming.