Composition: Cu-48%Zn (β´ brass).

Processing: Sand casting.

Etching: 1 min immersion in FeCl₃ alcoholic solution.

According to the Cu-Zn phase diagram, this alloy lies in the β monophasic region at high temperatures and in the β´ region below 454-468ºC. The β´ phase is brittle, but this alloy still finds application as a filler metal in welds and for casting of complex geometries. The microstructure reveals a radial distribution of columnar grains typically formed during casting of pure metals and monophasic alloys. An irregular distribution of equiaxial grains is found in the periphery of the specimen, indicating non-uniform cooling of the mold walls. At high magnification, the alloy only shows one phase and there are no signs of microsegregation. At triple junction grains meet at an angle of 120º due to equilibrium of grain boundary surface tensions.

Cu-Zn diagram

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