Materials science

D 1 grade duralumin (3.8...4.8% copper, 0.6% magnesium, 0.6% manganese, 0.7% silicon, the rest is aluminum) is a sufficiently refined and plastic alloy. Sheets, rods, pipes and other products are made from it by rolling and pressing . If duralumin is soaked in water at a temperature of 18...20 510⁰C^{0 C} for several days and nights , its structure consists of a solid solution of copper in aluminum and is visible under a microscope in a light color (Fig. 16.6, a). The mechanical properties of natural weathered D1 duralumin are as follows: s _g =36 ... 38kgk/mm ² , s _ok =22 ... 25kgs/mm ² , s =10 ... 12%.
B 83 babbitt (83% tin, 11% antimony, 6% copper) is a corrosion-resistant, heat-conducting, high-pressure alloy used to reduce friction, with sufficient mechanical properties. (they are used to make various sliding bearings). The structure of this alloy consists of a dark-colored plastic base, a phase - a solid solution of antimony and copper in tin, liquid-colored SnSb crystals and crystals of Cu ₆ Sn _{5 composition (Fig. 16.6, b).}
Hard alloys of the VK brand are often used to make drill bits in drilling operations . Figure 16.7 a The microstructure of VK 15 hard alloy is presented. Its white plates are WC, black spots are cobalt metal.

Figure 16.7. Microstructure of hard alloy VK 15, x 500.

Necessary equipment, materials and tools for the work: when familiarizing with non-ferrous metals, samples of different brands are taken, clamps are used for grinding, metallographic microscope is used for observing their structures, as well as a barbell circle .

Thermal treatment of duralumin alloy
Purpose of work: Finding alloy D 16 and artificially aging it at temperatures of 100⁰ C, 200 ⁰C, 300 ⁰ C and learning to draw a graph of the hardness of this alloy and dependence on aging temperature.