Fabrication and evaluation of the tubed functionally gradient material by slurry dipping

Watanabe, Ryuzo*; not registered

This report is the PNC contract research for fiscal year of 1993 titled "Formation of Ti/SUS/Mo graded layer by slurry dipping." Fuel sheath material for FBR is used under a severe enviroment. The life of conventionally used SUS316 is known to be only two years. The development of long-life core material having high temperature strength, radiation resistance and anti-corrosion property is now essential. To create a super-long-life core materials for FBR it seems promising to employ the concept of functionally gradient material, in which these different materials are configurated with grading : as base material is used SUS316 stainless steel, the inner wall is made of Ti for the radiation resistant and anti-corrosion property with graded intermediate layers towards the base metal and the outer shell is the graded Mo layer for the corrosion resistance against liquid sodium. The shape of the core tube is a long cylindrical tube and its dimensions are 8.5mm in outer diameter, about 2m in length, shell thickness is 0.5mm and the thickness of the gradient layer is about 0.1mm. However, we have not yet acquired sufficient techniques to realize such shape and dimmensions, and the investigation is planned to get basic informations on the processing of the core materials with graded structures. Slurry dipping has been employed for forming a graded layer on curved inner and outer surfaces. And it is indispensable that the graded layers have showed sufficient thermal-stress relief function, as well as good bonding capability. In this year (FY 1993), the formation of the graded inner layer of Ti/SUS316 by slurry dipping was investigated. The formation procedure is briefly mentioned here as follows. Cylindrical green compacts of SUS304 stainless steel powder was prepared by die compaction and CIP as a substrate for slurry dipping. A coarse Ti powder was suspended in ethanol and milled by tumbler ball mill to get a slurry having an appropriate viscosity for dipping. The ...