Study On Superplastic Micro-forming Process Of Zr-based Bulk Metallic Glass

Bulk metallic glass was considered as one of the most potential materials because of the excellent super-plastic forming ability in the supercooled liquid region and mechanical properties in micron-size. In this paper, the superplastic hot embossing micro-forming technology of the bulk metallic glass was studied, which the composition elements ratio was Zr65Cu17.5Ni10Al7.5. Content as described below:The thermal stability of the samples, associating with the glass transition and crystallization, were examined by differential scanning calorimetric (DSC) to determine the temperature of supercooled liquid region, and the time-temperature-transformatiom (TTT) curve of the samples was obtained. Then, the compression strength at room temperature and the superplastic uniaxial compression performance at the supercooled liquid region have been tested by the Zwick Roell testing machine. The isothermal oxidation behavior has been researched by thermo-gravimetric analyzer (TGA). The studies provided the experimental basis for the papmeters option of the superplastic hot embossing micro-forming technology.The metal mold prepared by the femto-second laser processing technology was used to the superplastic hot embossing micro-forming technology of bulk metallic glass, and the armphous micro-part was prepared. Superplastic micro-forming of bulk metallic glass with silicon mold using hot embossing technology was studied, which was the firstly in china. The silicon mold prepared by the bulk silicon processing technology was used to forming the armphous micro-parts. The finite element simulation software DEFORM-3D was used to analysis the filling process in the silicon mold. The forming load was predicted, and the punch velocity was optimized. Finally, a good dimensional accuracy for a micro-spur gear with 0.1 module,20 teeth and a spline structure in the core was obtained by superplastic hot embossing forming technology.The process parameters of forming more than one at one time were studied, including the structural design of micro silicon mold, the thickness of silicon mold sidewall and the size and shape of blank. The forming process programs of complex multi-dimensional microstructure were designed using the multi-dimensional silicon mold. The complex amorphous multi-gear microstructure was prepared.3K-1 type micro planetary gear reducer was designed. The forming process programs of the micro-parts used in the micro planetary gear reducer were analyzed and testing studied. The armphous micro-parts were prepared.The study of bulk metallic glass was attentioned due to the excellent performance. The manufacture of the high performance micro-parts has broad application prospects basing on the superplastic forming techonology. The research on the micro-forming of bulk metallic glass was still in the initial stage. The preparetion of the complex three-dimensional micro-structure/parts basing on the superplastic micro-forming technology needs further study.