Co-deformation processing and modeling of In-Situ multiphase composites

Abstract

A series of in-situ, deformation-processed metal matrix composites were produced by direct powder extrusion of blended constituents. The resulting composites are comprised of a metallic Ti-6Al-4V matrix containing dispersed and co-deformed discontinuously reinforced-intermetallic matrix composite (DR-IMC) reinforcements. The DR-IMCs are comprised of discontinuous TiB 2 particulate within a titanium trialuminide or near-␥ Ti-47Al matrix. Thus, an example of a resulting composite would be Ti-6Al-4V ϩ 40 vol pct (Al 3 Ti ϩ 30 vol pct TiB 2 ) or Ti-6Al-4V ϩ 40 vol pct (Ti-47Al ϩ 40 vol pct TiB 2 ), with the DR-IMCs having an aligned, high aspect ratio morphology as a consequence of deformation processing. The degree to which both constituents deform during extrusion has been examined using systematic variations in the percentage of TiB 2 within the DR-IMC, and by varying the percentage of DR-IMC within the metal matrix. In the former instance, variation of the TiB 2 percentage effects variations in relative flow behavior; while in the latter, varying the percentage of DR-IMC within the metallic matrix effects changes in strain distribution among components.The results indicate that successful co-deformation processing can occur within certain ranges of relative flow stress; however, the extent of commensurate flow will be limited by the constituents' inherent capacity to plastically deform.

Very-high-precision bound-state spectroscopy near a85RbFeshbach resonance

“…Another example of the accuracy of the analysis in Ref. [15] is its agreement with more than 40 Feshbach resonances recently discovered in 87 Rb [23].…”

“…Therefore, we take the mean values for these four parameters [24] from the most recent determination in Ref. [23].…”