The consolidation of rapidly solidified particulate by dynamic compaction and hot-isostatic pressing

This work examined the consolidation processing of rapidly solidified particulate and applied a relatively new consolidation technique, namely dynamic compaction (DC), to the problem and investigated a novel processing route involving both dynamic compaction and the relatively conventional technology of hot-isostatic pressing (HIP) in which dynamically consolidated pieces were subsequently HIP'd at low temperatures in a hybrid process termed DC-HIP.; The effect of dynamic compaction on as-rapidly solidified particulate was examined and very little evidence of thermal degradation was observed in the as-rapidly solidified microstructures. Interparticle melt zones were identified in dynamically compacted material by analytical electron microscopy techniques. Additionally, the mechanisms of heat generation and melting were identified. The effect of subsequent HIP on the rapidly solidified microstructure of dynamically compacted pieces was also examined and found to be negligible in almost all cases.; The mechanical properties of materials consolidated by dynamic compaction and by DC-HIP were compared to those of conventionally HIP'd material. Generally, the mechanical properties of the materials processed by DC or DC-HIP were equivalent to those of HIP'd material. In general, poor interparticle bonding is the principal factor in limiting strength of materials consolidated by DC or DC-HIP while inferior microstructures limited the strength of conventionally HIP'd material.; Finally, the effect of plastic deformation and applied stress on enhanced decomposition of rapidly solidified microstructures in Al-8Fe-2Mo and Ti-Er alloys was also examined. The results indicated that there is little effect of either plastic deformation or applied stress on decomposition of the Zone A microstructure in Al-8Fe-2Mo. The effect of plastic deformation and applied stress on microstructural degradation of erbia strengthened Ti-Er alloys was found to be significant, the extent of coarsening as identified by average particle size increasing as a result of plastic deformation and with increased applied stress. The difference in enhanced decomposition behavior between these two microstructures was concluded to be a result of the mechanism of microstructural degradation and atomic transport.