Experiment Study on Beryllium and Copper Alloy Joints by Hot Isostatic Pressing Bonding

摘要

Performances of Be/Cu joints fabricated by hot isostatic pressing (HIP) bonding were studied by means of various test methods, such as shearing test, scanning electron microscopy(SEM) observation, energy dispersion spectrometer(EDS) and X-ray Diffraction (XRD) analysis, when Ti (PVD-coated on Be)/Cu (PVD- coated on CuCrZr) interlayers were used. This study considered several diffusion surface treatments (such as chemical etching, polishing, etc.) for minimizing or eliminating the effects of the oxide film on beryllium to promote good diffusion bond between these materials. Experiments indicated that the joints HIPed at 580℃/145MPa/2h showed high shearing strength (up to123MPa) at room temperature and no defect such as cracks was observed at the bonding interface dut to the role of the etching with a dilute acid solution to remove native oxide films on beryllium surface prior to titanium coating. The strength moderately decreased when the diffusion holding time increased from 2h to 4h. The thin titanium diffusion barrier (~10μm) which was coated on the beryllium surface have prevented the reaction between Be and Cu, but CuTi phase was formed at Ti/Cu interface. It is considered the phase limited the bonding strength to higher level.