抽拉速率对Co-Al-W基单晶高温合金凝固行为的影响  

Effect of withdrawal rate on solidification behavior of Co-Al-W based single crystal superalloy

作　　者：艾诚 王国鑫 陈曦 郭敏[3] 黄太文[3] 刘林[3] AI Cheng;WANG Guo-xin;CHEN Xi;GUO Min;HUANG Tai-wen;LIU Lin(School of Materials Science and Engineering,Chang’an University,Xi’an 710064,China;Xi’an Saite Simai Titanium Industry Co.,Ltd.,Xi’an 710018,China;State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China)

机构地区：[1]长安大学材料科学与工程学院,西安710064 [2]西安赛特思迈钛业有限公司,西安710018 [3]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《中国有色金属学报》2023年第6期1831-1841,共11页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(52071267,51971174);中央高校基本科研业务费(300102311401,300102312407)。

摘　　要：系统地研究抽拉速率(50~300μm/s)对Co-7Al-8W-1Ta-4Ti单晶高温合金枝晶间距、显微组织、显微偏析行为与凝固特征温度等凝固行为的影响规律;同时,基于Kurz-Fisher方程计算了单晶高温合金的平均液相扩散系数。结果表明,随着抽拉速率的提高,合金的一次和二次枝晶间距均显著细化。Co-7Al-8W-1Ta-4Ti合金的平均液相扩散系数与一代镍基单晶高温合金接近,低于高x(Al)/x(W)的CoNi基单晶高温合金,但高于含Re的二代镍基单晶高温合金。合金中Al、W、Ta和Ti元素的显微偏析倾向以及枝晶间析出相的面积分数均随着抽拉速率的提高总体呈现先增大(50~200μm/s)后降低(200~300μm/s)的趋势。随着抽拉速率的提高,合金的液相线温度基本不变,但固相线温度呈现先降低(50~100μm/s)后保持不变(100~300μm/s)的趋势。此外,抽拉速率未改变实验合金的凝固路径。The influences of withdrawal rate(50−300μm/s)on dendrite arm spacing,microstructure,microsegregation behavior and solidification characteristic temperatures of Co-7Al-8W-1Ta-4Ti single crystal superalloy were systematically studied in this investigation.Meanwhile,the average liquid diffusion coefficient of single crystal superalloy was calculated based on Kurz-Fisher equation.The results indicate that the primary and secondary dendrite arm spacing is significantly refined with increasing withdrawal rate.And the average liquid diffusion coefficient of Co-7Al-8W-1TA-4Ti alloy is close to that of first-generation Ni based single crystal superalloy,and lower than that of CoNi based single crystal superalloy with high mole fraction ratio of Al and W,but higher than that of second-generation Ni based single crystal superalloy.Moreover,the microsegregation degree of Al,W,Ta and Ti elements and volume fraction of the interdendritic precipitations firstly increase(50−200μm/s)and then decrease(200−300μm/s)with increasing withdrawal rate.In addition,with increasing withdrawal rate,the liquidus temperature basically remains unchanged,while the solidus temperature firstly decreases(50−100μm/s)and then remains unchanged(100−300μm/s).In addition,the withdrawal rate does not change the solidification path of experimental alloy.

关 键 词：Co-7Al-8W-1Ta-4Ti单晶高温合金 抽拉速率 枝晶间距 平均液相扩散系数 枝晶间析出相 显微偏析 凝固特征温度 凝固路径 

分 类 号：TG132.3[一般工业技术—材料科学与工程]