Application of Experimental Design Techniques to Identify the Key Processing Parameters of Various CP Grade Ti Powders

摘要

In order to achieve optimum density with minimum porosity of hot consolidated CP grade Ti powders, it is important to understand the interaction between particle size distribution, morphology, green density and hot consolidation parameters (pressure/temperature). Using angular hydride/dehydride and sponge derived powders of varying particle size distributions; an experimental design approach was adopted with net density and compact height reduction employed as the ranking criteria. In addition, an image analysis technique was adopted to quantify the radial and axial porosity distributions as a secondary ranking criteria. Statistical analysis of the results determined that for optimum as-pressed density, green compaction density was the most important factor and the temperature of hot pressing was the least important over the range evaluated. This ranking was different to that observed in the compact height reduction, where pressing temperature was far more significant than particle size distribution. The outputs of this study have assisted the identification of a number of key characteristics of the Ti powder feedstock and its application to static and dynamic consolidation processes. This includes efforts to establish a process for the production of low cost thin titanium sheet from powder feedstock on a continuous basis.