The Influence Of Investment Casting On The Mechanics Performance Of Ear-Flake

Ear—flake used for aero-engine is applied at spout part under the circumstances of big load and high temperature more than 600℃.The supporting status of the cast is heat treatment and its characteristics is very strict.especially the general characteristic of the durability under the circumstances of long working time more than 100 hours along with high temperature more than 600℃and high stress about 590 MPa is much more stricter.At present,the homemade cast according to the foreign standards can hardly meet the requirement.Even if one or two group of cast is eligible,the safety coefficient of the performance index of the eligible cast parts is not big enough.At the same time,during the chemistry composition analysis of foreign raw materials,we found that there is Mg element in the raw material,which is not mentioned in current foreign material standards and domestic profession standards.The material of ear-flake isВЖЛ—14 superalloy.Taking into account of the reasons above,the sudy about the cast temperature and molding shell status influencing on mechanic performance is taken up.On the base of keeping the original alloy elements, according to Ni-base superalloy strengthen characteristics at high temperature,the proportion of the main strengthening element in the superalloy such as Al,Ti,Cr,Mo,B are adjusted so as to study the influence on the mechanics performance.Simultaneously, some Mg elements are properly added and studied.The result shows us that:compared with the filled sand cast sample,the durability of the single shell cast sample is similar and the tensile strength is better,but the strick tenacity is worse.the cast temperature of the sample is made certain at the temperature between 1400℃and 1420℃.the main strengthening element in the superalloy such as Al,Ti,Cr,Mo separately contribute to increasing the amount ofγ′phase and MC phase,strengthing theγ′base andγ′phase so as to improve the mechanic characteristic of superalloy.If the Mg element is added properly,the configuration of the carbides along the grain boundary can be improved obviously,and the strick tenacity of the superaUoy can be improved obviously.the durability study of the ear-flake show us that the crack under high-cycle fatigue at room temperature generate mainly on the sample surface or at the defect near the sample surface.while the the crack under high-cycle fatigue at high temperature generate mainly at the inside defect of the sample.The research in this paper has given us a convincing theoretics basis for improving the mechanic characteristic of ear-flake and a good reference for development ofВЖЛ—14 superalloy.