钛铝低压涡轮叶片熔模铸造精确成形及冶金缺陷分析  

Precise Forming and Metallurgical Defects of TiAl Low Pressure Turbine Blade by Investment Casting

作　　者：朱郎平 李建崇 张美娟 魏战雷 黄东 南海 ZHU Lang-ping;LI Jian-chong;ZHANG Mei-juan;WEI Zhan-lei;HUANG Dong;NAN Hai(AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China;Beijing Engineering Research Center of Advanced Titanium Alloy Precision Forming Technology, Beijing 100095, China)

机构地区：[1]中国航发北京航空材料研究院,北京100095 [2]北京市钛合金精密成形工程技术研究中心,北京100095

出　　处：《精密成形工程》2018年第3期87-92,共6页Journal of Netshape Forming Engineering

基　　金：北京市科技计划专项(Z171100002217012);国家自然科学基金(51671026);装备预研基金(6140922020107)

摘　　要：目的研究不同浇冒口设置对Ti Al低压涡轮叶片的成形的影响及叶片冶金缺陷形成的原因。方法采用熔模精铸方法,通过设计顶注式重力铸造浇注系统,采用冷坩埚感应熔炼炉进行Ti Al叶片浇注实验,采用目视和X射线检验方法分析叶片铸件表面及内部缺陷,并结合金属凝固理论分析缺陷形成原因。结果合理的浇口和排气孔设置有效避免了因熔体流动性差造成的叶片充型不完整,以及凝固收缩导致的应力开裂等问题,浇注出成形完整的铸造叶片;叶冠与叶身端部转角部位充型凝固过程中形成热节,容易出现贯穿性疏松缺陷;树脂基熔模焙烧后残留的碳黑在熔体充型凝固过程中,与面层中的Zr O2反应生产CO,导致叶身出现聚集性皮下气孔;由于凝固收缩引起叶身与铸型分离,降低横向散热能力,导致叶盆部位出现表面疏松。结论通过浇注合理的浇注系统设置可实现Ti Al叶片完整充型,疏松缺陷控制为进一步提高叶片质量的关键。The paper aims to study influences of different sprue and risers setting on forming of TiAl low pressure turbine blades and the reasons for its metallurgical defects. The investment casting method was adopted and top gating system of gravity casting was designed to carry out TiAl blade casting experiment with cold crucible induction melting furnace. Internal and ex-ternal metallurgical defects were respectively inspected by visual inspection and X-ray inspection technology, and the cause of defect formation was deduced by metal solidification theory analysis. It was evitable to prevent misrun cause of low melt fluidi-ty and cracking cause of shrinkage stress by setting up reasonable gate and vent, and acquire complete blade casting. Hot spot prone to form in the corner of the shroud and blade body during filling and solidification process, which lead to penetrating po-rous defects. Carbon black brought by sintering of residual resin reacted with ZrO2 in investment precoat, resulting in aggregat-ed distribution of subsurface blowhole. Separation of the blade body and the mould caused by solidification shrinkage reduced the ability of transverse cooling, leading to formation of surface porosity. Complete filling of TiAl blades can be achieved byreasonable setting of pouring system. While the control of porous defects is the key to further improve the quality of the blades.

关 键 词：熔模精密铸造 TIAL金属间化合物 低压涡轮叶片 重力浇注 冶金缺陷 

分 类 号：TG146.2[一般工业技术—材料科学与工程]