Physical and foundry propertiesof Cu-Sn-Al system alloys

Abstract

Tin-aluminum bronze containing Sn - up to 6.73% and Al - up to 7.53% (by weight) physical and casting properties determination. Methodology. Melting has been carried out in graphitecrucible in induction furnace under charcoal layer. Alloys liquidus and solidus temperatures have been investigated by thermography results of solidifying melt. Free (С) and absolutely difficult (АЗ) linear shrinkage values and alloy transition temperature from plastic to elastic state during cooling in mold have been studied by conventional methods. Bronzes fluidity has been estimated by the spiral sample filled channel length according to GOST 16438. Bronze BrO3A3 tendency to burn and to hot and cold cracks formation has been evaluated by samples surface visual examination results. Cast bronze specific density has been determined by calculation. Studied alloys mechanical properties have been calculated based on corresponding samples tests results at their impact bending at room temperature in accordance with actual standards. Alloys chemical composition control has been carried out on precision analyzer EXPERT 4L on specimens cut from club-shaped samples. Microstructural studies have been performed on metallographic microscopic samples prepared by standard methods on optical microscope Neophot-21. Approximation reliability value and corresponding dependences have been built using EXEL computer program. Results.According to qualitative and quantitative indicators and system Cu-Sn-Al bronzes with Sn content up to 6.73% and Al content up to 7.53% physical and foundry properties assessments, it has been determined that among possible tin and aluminum content in Cu-Sn- Al the most promising is bronze with 3...4% (by weight) of these alloying components each. Originality.For the first time number of physical and foundry properties of Cu-Sn-Al system bronze (with Sn content up to 6.73% and Al up to 7.53%) have been determined. It has been first established that such bronzes linear shrinkage, transition temperature from plastic to elastic state during cooling after solidifying and impact bending value at normal temperature depend on their structure, i.e. phase composition determined by its alloying elements content in bronze. Practical value.According to studies of physical and foundry properties results, bronze BrO3A3 has been recommended to be used as casting material