钛合金熔模铸造二醋酸锆-氧化钇型壳的回溶及影响（英文）  

Mechanism and Influence of Re-dissolution of Zirconium Diacetate-Yttria Shell for Titanium Investment Casting

作　　者：郭馨[1,2] 吕志刚[1,2] 李培杰[1] 

机构地区：[1]清华大学,北京100084 [2]先进成形制造教育部重点实验室,北京100084

出　　处：《稀有金属材料与工程》2016年第2期303-308,共6页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(50875144)

摘　　要：研究了二醋酸锆-氧化钇型壳(ZA-Y型壳)的回溶及其影响。使用重量法测定了型壳热水、蒸汽条件下的回溶率;使用电子万能试验机测定了型壳抗弯强度,并计算了裂纹指数随润湿时间的变化规律;利用光学显微镜(OM)观察了表面析出物的分布情况,用扫描电镜(SEM)结合能谱分析(EDS)研究了其形貌与成分,使用X射线荧光分析(XRF)方法测定了ZA-Y型壳的成分,并分析了表面析出物产生的原因。结果表明,型壳20 min内的回溶程度有限,最大吸水率为2.5%,回溶率为0.8%;强度下降26%,但裂纹指数下降至66%;表面析出物主要是由于偏钨酸铵的回溶,包含2种原因:泄压速度过快或后续干燥快而散热慢。The re-dissolution of zirconium diacetate-yttria shell（ZA-Y shell） and its impact were investigated. The re-dissolution rate under moisture condition was measured by a balance. Three-point flexural strength was measured using a universal testing machine, and the fracture index was calculated. The distribution of the surface precipitates was observed by optical microscope, and its morphology and composition were tested using scanning electron microscopy（SEM） combined with energy spectrum analysis（EDS）. The composition of the ZA-Y shell was measured by X-ray fluorescence（XRF）. The results show that the re-dissolution is limited. The maximum water penetration rate is 2.5% and the dissolution rate is 0.8% within 20 min. The strength decreases by 26% and fracture index reduces to 66%. The surface precipitates are attributed to dissolution of ammonium metatungstate（AMT） and there are two reasons： drastic pressure release or fast drying condition with slow heat dissipation.

关 键 词：钛合金 熔模铸造 回溶 强度 析出物 

分 类 号：TG292[金属学及工艺—铸造]