The recent research of the alternate sliding bearing materials unequivocally points to the beneficial role of Lead (Pb) in Aluminum (Al). But, these alloys offer a manufacturing challenge, due to wide immiscibility gap. For such applications, apart from homogeneous microstructure, porosity control is also equally important, as it influences the tribological performance through spreading of Lead in Aluminum matrix. These objectives can be achieved by mechanical alloying through attrition milling. In order to control the shape of the final Powder Metallurgical (P/M) parts, appropriate models are necessary for densification of composite powders to simulate cold compaction responses. In the present work, the authors studied the effect of alloy composition and the ball to charge ratio on the densification behavior of attrition milled Al-Pb alloys, with a view to develop nonlinear regression models that can best describe the densification behavior of attrition milled Al-Pb alloys, from compressibility test data.

Powder Metallurgical (P/M) processing produces materials of extremely fine and uniform microstructure and permits the forming of a material composed of different constituents yielding unique combinations of properties. However, powder metallurgical processing quite often yields materials containing a substantial amount of residual porosity or impurities along particle boundaries. Both effects have a detrimental effect on material properties (Kuhn, 1978). Successful utilization of the process depends on many factors. These include careful control of the deformation, elimination of flash formation and, perhaps the most important, proper densification.

In the manufacturing technologies of P/M products, die compaction is widely used. However, P/M parts formed by die compaction have inhomogeneous density distributions due to friction between the powder and the die well. Inhomogeneity in density leads to non-uniform shrinkage or distortion during the sintering process, and thus makes it difficult to control the shape of final P/M parts (Lee and Kim, 2002). In order to control the shape of final P/M parts, the appropriate models are necessary for densification of composite powders to simulate cold compaction responses. Theories describing the deformation of porous material are enumerated and the changes in density during the powder forming process are analyzed with the help of a theoretical and numerical analysis by Bruhns and Sluzalec (1993) to model the densification behavior of porous materials.

Mechanical Engineering Journal, Al-Pb Alloys, Nonlinear Regression Models, Powder Metallurgical Processing, P/M Products, Soil Mechanics, Drucker-Prager Model, Hyperbolic Cap Model, Aluminum Alloy Powder, Logistic Model, Data Modeling Equations, Aluminum Alloys.