Enhancement of the Mechanical Properties of Al-Pb Alloy using an Equal Channel Angular Pressing Process

摘要

Aluminium-lead alloys are considered to be vital materials for the 21~(st) century, and applications of these alloys are used in a great many heavy-duty roles such as boring mills, presses, lathes, milling machines, and hydraulic pump bushings. In this work, an equal channel angular pressing (ECAP) process was used to enhance the mechanical properties of Al-Pb bearing alloy prepared using a mechanical alloying method. This work is divided into two main parts: Part I deals with the production of rectangular billets of 15 × 15 × 45 mm~3 in size constructed by mixing powders of Al-10%Pb-4.5%Cu by weight for two hours using a ball milling process. The mechanical properties obtained for these alloys were 191 MPa compressive strength and 50 HV micro hardness. Part II is concerned with the design and manufacture of an ECAP die for a channel angle of 135° with multi passes using rout Bc radius of curvature with inner radius R equal to 15 mm and outer radius r equal to 5 mm suitable for the chosen alloy. The billet produced in part I was then preheated and pressed through the ECAP die. The results obtained from the experimental work showed an increase in mechanical properties: the enhancement of compression strength reached 38%, and that of micro hardness 28% in the first pass; further enhancements of compression strength and micro hardness were 44% and 36% respectively in second pass, without any reduction of ductility in the alloy.