冷却速率对Ti-48Al-2Cr-2Nb合金组织及性能的影响  

Effect of Cooling Rate on Microstructure and Propertie of Ti-48Al-2Cr-2Nb Alloy

作　　者：包春玲[1] 谢华生[1] 赵军[1] 张有为[1] 

机构地区：[1]沈阳铸造研究所,高端装备轻合金铸造技术国家重点实验室,辽宁沈阳110022

出　　处：《铸造》2016年第12期1210-1213,共4页Foundry

摘　　要：TiAl基合金铸造成形过程多采用陶瓷型、金属型,少量涉及石墨型,文中对比石墨型、金属型和陶瓷型成形Ti-48Al-2Cr-2Nb合金的凝固组织及力学性能,研究冷却速率对凝固组织及力学性能的影响规律。研究结果表明:采用冷却能力较强的石墨型成形Ti-48Al-2Cr-2Nb合金的组织层片间距最小,金属型的次之,而采用陶瓷型成形的组织层片间距最大。通过对Ti-48Al-2Cr-2Nb合金宏观组织特征的分析,总结一种评价铸型冷却能力的方法。通过对显微组织层片间距的定量统计分析,测量出三种铸型条件下,石墨型和金属型的试样层片间距相近,无明显差别,而陶瓷型的试样层片间距明显高于其他两种。铸型的蓄热系数和热导率是影响Ti Al合金组织和力学性能的主要因素。In most cases, ceramic molds, pemanent molds are used and in a few cases, graphite molds are applied in the casting forming process of TiAl based alloy. In this paper, macrostructure, microstructure, and mechanical properties of Ti-48Al-2Cr-2Nb alloy using graphite mold, pemanent mold, ceramic mold and the influence law of solidification rate on structure, and mechanical properties have been comparatively studied. The results show that lamellar spacing of Ti-48Al-2Cr-2Nb alloy using graphite mold with high cooling ability is minimum, followed by pemanent mold＇s, while ceramic mold＇s is maximum. By the characteristics analysis of macrostructure of Ti-48Al-2Cr-2Nb alloy, a method for evaluating cooling capacity of mold was formed by the quantitative statistical analysis of lamellar spacing, the lamellar spacing of samples with graphite mold and pemanent mold are no significant difference, and the lamellar spacing of samples with ceramic mold is obviously higher than the other two. Heat storage coefficient and thermal conductivity of molds are major influence factors on structure and mechanical properties of Ti-48Al-2Cr-2Nb alloy.

关 键 词：TIAL基合金 石墨型 金属型 陶瓷型 蓄热系数 热导率 

分 类 号：TG146.23[一般工业技术—材料科学与工程]