Investigation on wear and corrosion behavior of equal channel angular pressed aluminium 2014 alloy

Aluminium 2014 alloy solutionized at 495°C, aged at 195°C was subjected to Equal Channel Angular Pressing (ECAP). Dry sliding wear tests were conducted using pin on disc tribometer system under nominal loads of 10N and 30N with constant speed 2m/s for 2000m in order to investigate their wear behavior after ECAP. The Co-efficient of friction and loss in volume were decreased after ECAP. The dominant wear mechanism observed was adhesion, delamination in addition to these wear mechanisms, oxidation and transfer of Fe from the counter surface to the Al 2014 pin were observed at higher loading condition. The corrosion behavior was evaluated by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. The results obtained from PDP showed higher corrosion potential and lower corrosion density after ECAP than base. Electrochemical impedance spectroscopy (EIS) showed higher charge transfer resistance after ECAP. Surface morphology showed decreased pit size and increased oxygen content in ECAP sample than base after PDP

A beginner's guide to the use of the spectral collocation method for solving some eigenvalue problems in fluid mechanics

The present quot;Guidequot; aims to introduce- through selected examples the use of the spectral collocation method for solving eigenvalue problems. The focus of attention in the quot;Guidequot; is the recasting of the differential eigenvalue problem into its algebraic counterpart (matrix eigenvalue problem). Starting from an outline of the method, the steps of discretisation and transformation according to the spectral collocation method are illustrated in detail for the selected examples ordered according to increasing complexity. The two simple examples are differential equations of second and fourth order with constant coefficients. The chosen example from fluid mechanics is the propagation of small amplitude disturbances in the fully developed channel flow 13; (Orr-Sommerfeld equation). The quot;Guidequot; includes FORTRAN source programs for the examples.13; 13; 13