TiAl基合金铸件特征结构及型壳固液比对铸造缺陷影响  

Effect of Characteristic Structure and Shell Solid-Liquid Ratio on Casting Defects of TiAl Based Alloy Castings

作　　者：张扬晟 胡海涛 左家斌 冯新 南海 丁贤飞 ZHANG Yang-sheng;HU Hai-tao;ZUO Jia-bin;FENG Xin;NAN Hai;DING Xian-fei(AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;Bejing Engineering Research Center of Advanced Titanium Alloy Precision Forming Technology,Beijing 100084,China;BIAM Co.,Ltd.,Beijing 100094,China)

机构地区：[1]中国航发北京航空材料研究院,北京100095 [2]北京市先进钛合金精密成型工程技术研究中心,北京100084 [3]北京航空材料研究院股份有限公司,北京100094

出　　处：《精密成形工程》2022年第11期170-183,共14页Journal of Netshape Forming Engineering

基　　金：国家科技重大专项(J2019-VI-0003-0116)。

摘　　要：目的揭示铸件结构特征及型壳固液比差异对铸件充型率、收缩率和内部缺陷倾向性的影响。方法分别采用3种不同型壳固液比的型壳,通过重力浇注制备了Ti−48Al−2Cr−2Nb合金特征结构元件铸件,对具有不同尺寸参数的板、变截面、尖角、筋、过渡弧、孔、环、曲面等8种典型特征结构元件铸件的充型率、收缩率、缩松/气孔的数量与分布、截面缩松率等铸造成形特性进行研究。结果板厚度≥6 mm、变截面厚度变化率≥0.075、尖角≥90°时可基本充型完整;铸件收缩率在1.8%~3.3%之间;在不同特征结构中,变截面的平均截面缩松率最低为0.012%~0.018%,尖角最高为0.21%~0.46%;型壳固液比为1.8∶1和2∶1的铸件气孔分布面积仅为2.4∶1时的10%~80%。结论充型高度随铸件厚度和角度增大而提高;特征结构与尺寸参数对收缩率影响较小;铸件的壁厚、厚度变化率、角度和孔径等因素均会对缩松的数量与分布产生影响;型壳固液比为1.8∶1和2∶1的铸件气孔分布面积比普遍低于2.4∶1的铸件。相关结果为钛铝合金复杂构件结构设计优化和精铸成型工艺优化的共性技术发展提供了支撑。The work aims to reveal the influence of the structural characteristics of the casting and the difference of the solid-liquid ratio of the mold shell on the filling rate,shrinkage rate and internal defect tendency of the casting.Ti-48Al-2Cr-2Nb alloy structural element castings were prepared by gravity casting with three different solid-liquid ratio shells.The casting formability of 8 typical characteristic structures(plate,variable section,sharp corner,reinforcement,transition arc,hole,ring and curved surface)with different size parameters,such as filling rate,shrinkage rate,number and distribution of shrinkage/porosity and section shrinkage rate,was studied.The results show that,when the thickness of the plate is≥6 mm,when the thickness change rate of the variable section is≥0.075,and when the Sharp corner is≥90°,the mold filling is basically complete.The shrinkage rate of the casting is between 1.8%and 3.3%.Among the different characteristic structures,the average section shrinkage porosity of variable section is 0.012%-0.018%,and that of Sharp corner is 0.21%-0.46%.When the solid-liquid ratio of the mold shell is 1.8∶1 and 2∶1,the porosity distribution area of the casting is only 10%-80%of that under 2.4∶1.The conclusion is that the filling height increases with the increase of casting thickness and angle.The structure and size of various features have little influence on shrinkage.The factors such as wall thickness,thickness change rate,angle and pore diameter of the casting will affect the quantity and distribution of shrinkage porosity.When the solid-liquid ratio of the mold shell is 1.8∶1 and 2∶1,the air hole distribution area ratio of the casting is generally lower than that under 2.4∶1.The relevant results provide a favorable support for the development of common technology of structural design optimization and precision casting process optimization of titanium aluminum alloy complex components.

关 键 词：TIAL 铸造 特征结构 固液比 收缩率 缺陷 

分 类 号：TG27[金属学及工艺—铸造]