Development of Porous Beryllium by the Hot Isostatic Pressing of Plasma-Spheroidized Powder.

摘要

Spheroidal beryllium powder in the nominal 40to 50-micron size range was prepared from irregular starting material by plasma spheroidization. An effort was made to develop hot-isostatic-pressing parameters necessary to reproducibly fabricate porous beryllium billets from this powder possessing uniform permeabilities of 0.1, 0.01,and 0.001 darcy plus or minus 10percent. In the program,no billets were produced to the specified permeability of 0.1, 0.01,or 0.001 darcy plus or minus 10percent. Only one full-size billet,having a permeability of 0.017 darcy,was within the range of 0.1to 0.001 darcy. Reproducibility of the process was not established in this range as a second billet produced under identical conditions had a similar density but its permeability could not be determined. Data from billets outside the specified permeability range indicated that hot isostatic pressing of spherical powders has potential for the reproducible fabrication of porous beryllium billets as well as for achieving uniformity of permeability within the billets. However,development of a process to produce spherical powder in reasonable quantity would be required. The tensile strength,compressive strength,and modulus of rupture decreased linearly with decreasing density. Anticipated values of these properties,based on extrapolation,for permeabilities within the range of 0.1to 0.001 darcy would be 5to 15 x 1000psi, 20to 45 x 1000psi,and 10to 25 x 1000psi,respectively. (Author)