Experiments were carried out with 1 micron copper powder compacts containing up to 7.5 vol % .018 micron alumina, and with various types of lead powder compacts containing up to 20 vol % of various other materials. The results indicate that dispersion-hardened alloys should be divided into three groups on the basis of the nature of the second phase. i) particulate, adherent (not coherent) with matrix ii) particulate, non-adherent with matrix iii) semi-continuous It is suggested that the room temperature strengthening of the second and third groups of alloys may be due primarily to a grain size effect as described by the Hall-Petch relationship. The cell-like structure recently proposed for S.A.P. has been observed in the lead-lead oxide system by electron microscopy. An explanation of the difference in properties between extruded and rolled dispersion-hardened alloys has been offered in terms of the directional deformation caused by rolling. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

Thesis (Ph.D.) -- University of Texas at Arlington, 2008.

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg in partial fulfilment of the requirements for the Degree of Master of Science in Engineering. / A hydrochlorination facility was developed for tile processing of refinery precious metal residue materials on the laboratory and pilot scale. Hazard elements were identified and evaluated using an Event Tree Analysis. An exponential technique was applied to estimate the cost of the proposed production hydrochlorination facility. The estimated cost was R120 000. The Expected Present Value Ratio was +190 which indicated satisfactory project economics. The reactor material for the pilot scale unit was selected using a weighted values quantitative material selection procedure. Stainless steel Type 316L and Type 310 were selected. Failure of the Type 516L reactor occurred after 40 hours service. The mode of failure was extensive surface scaling which was attributed to the hydrogen chloride, sulphide gases and 1 000 °c operating envirornment. Subject to certain provisions it would be feasible to commission a safe and profitable production hydrochlorination facility. The consumable reactor concept was based on its replacement after 40 hours service. This was justifiable because of the high value of the material and the saving in down-stream processing costs. / Andrew Chakane 2018

Thesis (MEng (Metallurgical Engineering))-University of Pretoria, 2008. / Includes bibliographical references.

Thesis (M.Sc.)(Metallurgy)--University of Pretoria, 2004. / Includes summary. Includes bibliographical references.