Evaluation of Friction of Powder Metallurgical Al-4 wt% Cu Preforms by Employing Ring Compression Test and FEM in Hot Compression Test

摘要

In this investigation, the interface friction behaviour of powder metallurgical (P/M) Al-4 wt% Cu preforms was evaluated by using ring compression tests and finite element (FE) simulations at elevated temperature. P/M Al-4 wt% Cu ring specimens of different initial relative densities, 84, 87 and 90 %, were hot compressed at temperature ranging from 300 to 500 A degrees C under graphite lubricant and dry friction conditions. FE simulation was used to derive the calibration curves, analyze the densification behaviour and geometric changes and to evaluate the metal flow. Different interface heat transfer coefficients were used to generate friction calibration curves for graphite lubricant and dry friction conditions. The results revealed that increase in temperature or decrease in initial relative density increases the interface friction factor between tool and work piece. It was found that the influence of temperature was relatively less significant in dry friction than graphite lubricant condition. In addition, the effect of temperature, initial relative density and lubricating conditions on the densification behaviour, barreling phenomenon and metal flow was evaluated. FE simulations provided detailed and accurate results of the frictional behaviour at the tool-work piece interface, and hence employment of ring compression test with FE simulations is a reliable and feasible way to evaluate interface friction behaviour of P/M components in hot compression test.