INFLUENCE OF CORROSION ON MECHANICAL PROPERTIES AND MICROSTRUCTURE OF 3XXX, 5XXX, AND 6XXX SERIES ALUMINUM ALLOYS

Growing demands imposed on passenger car producers concerning the reduction of exhaust emission to the environment are forcing a search for new materials and design solutions. One of the most-important factors that can reduce this emission is the low mass of a vehicle, leading to a decrease in its average fuel consumption. A reduction in weight can be obtained by the use of aluminum elements instead of steel; e.g., in air conditioning pipes, decreasing the specific weight of the construction by nearly three times. In the present study, the influence of the SWAAT corrosion test on A/C piping made from 3xxx, 5xxx, and 6xxx series aluminum alloys was investigated. The study focused on changes in the mechanical properties of samples before and after a SWAAT test determined by a tensile test and Vickers hardness measurements. Additionally, microstructure examinations were performed with the use of optical and scanning microscopy. Corrosion products on the surface of pipes were identified by Energy Dispersive X-ray Spectroscopy. Pipes made from the EN AW 6063 alloy revealed an almost 50% decrease in its strength properties after the tests. The largest decline in plastic properties was observed in pipes made from the EN AW 6060 alloy

Effect of rapid solidification aluminum alloys with different Si content on mechanical properties and microstructure

Rapid solidification is a relatively new and effective way of ultrafine grained UFG aluminum alloys production with enhanced mechanical properties. Due to significant cooling rate close to almost 106 K/s it is possible to obtain material with grain size far below 100 nm. In the present study RS aluminum alloys with Si content in a range of 5-10 wt.% were produced during melt spinning. As a result, materials in a form of ribbons were produced. As-received flakes were subjected to cold pressing into a cylindrical billets with diameter of 40 mm. Hot extrusion of pre-compacted material was subsequently performed at the temperature of 450 °C with press ram speed of 3 mm/s and extrusion ratio of λ=25. In this work influence of brittle phases on mechanical properties of as-extruded rods will be examined. Both tensile and microhardness tests were performed in order to determine mechanical properties of obtained profiles. It has been showed that brittle phases refinement during melt spinning significantly influences mechanical properties of tested materials

SELECTION OF OPTIMAL CONDITIONS FOR SOLID BONDING OF THE AlSi11 ALUMINIUM ALLOY

In the present work, the optimal conditions for solid bonding of fragmented aluminum alloy were determined. The research was conducted on metal chips from the AlSi11 TM aluminum alloy after the turning process. The selection of proper bonding conditions was based on the results of tensile tests and surface quality analysis of as-extruded profiles. The extrusion process was conducted within a temperature range of 350–500°C, with a ram speed of 13 mm/s. Extrusion ratio λ was 25. As a reference material, a sample from the solid AlSi11IM alloy has been extruded under the same conditions.The influence of temperature during direct extrusion on both maximum force and surface quality of obtained profiles has been determined. With reference to tensile test results, no significant influence of temperature on the mechanical properties has been noticed. Profiles extruded at 500°C were characterized by visible cracks on the surface, oriented perpendicular in the direction of extrusion. Moreover, surface flaws were also noticed in profiles extruded at 350°C. A tensile testrevealed a strong relationship between the extrusion conditions and plasticity of solid bonded rods. A shiny and smooth surface was obtained only in profiles extruded at a temperature range of 400–450°C.Selection of optimal conditions for solid bonding of the AlSi11 aluminium allo

An Experimental Study of Temperature Effect on Properties of Nitride Layers on X37CrMoV51 Tool Steel Used in Extrusion Aluminium Industry

The paper concerns the effect of annealing time and temperature on the properties of the nitride layer on X37CrMoV51 tool steel used in the extrusion aluminium industry. Samples made from X37CrMoV51 steel were hardened and tempered, and then nitrided at 530 °C. After nitriding, the samples were annealed in a furnace at 470 °C for 8 h, 12 h, 24 h, 30 h and 60 h, and additionally for 20 h at 270 °C. The samples were tested for structure, hardness and abrasion immediately after nitriding and again after annealing. It was found that annealing the nitrided samples leads to degradation of the nitride layer, accounting for the decrease of hardness. The annealing of the samples at 470 °C, over 12 h causes a decrease in mean hardness value from 1176 HV to 1103 HV, and annealing the samples over 30 h at this temperature leads to a decrease in hardness to 964 HV. The changes in nitrogen content in the white (compound) and diffusion layers and the resulting consequences of changes in phase composition and properties were evaluated. Annealing over 30 h at 470 °C caused the white layer to disappear and the average nitrogen content in the diffusion layer to decrease to the level of about 5–6 at%