. The Iron and steel magazine. Fig. 28. Cu, 70%; Zn, 27%; Al, 3%.Magnified 200 diam. Fig. 29. Cu, 70%; Zn, 25%; Al, 5%.Magnified 200 Fig. 30. Cu,7o%; Zn, 22%; Al, 8%.Magnified 200 diam. Fig. 31. Cu, 70%; Zn, 20%; Al, 10%.Magnified 200 diam. of dark areas. The alloy containing 10 per cent aluminumwas so brittle that it was not possible to polish it. Passing tothe brasses containing 70 per cent copper, when the proportion Copper Alloys 127 of aluminum does not exceed 3 per cent the structure remains thatof ordinary brass. Upon exceeding that amount, large crystalsof forgeable brass appear
. The Iron and steel magazine. Fig. 28. Cu, 70%; Zn, 27%; Al, 3%.Magnified 200 diam. Fig. 29. Cu, 70%; Zn, 25%; Al, 5%.Magnified 200 Fig. 30. Cu,7o%; Zn, 22%; Al, 8%.Magnified 200 diam. Fig. 31. Cu, 70%; Zn, 20%; Al, 10%.Magnified 200 diam. of dark areas. The alloy containing 10 per cent aluminumwas so brittle that it was not possible to polish it. Passing tothe brasses containing 70 per cent copper, when the proportion Copper Alloys 127 of aluminum does not exceed 3 per cent the structure remains thatof ordinary brass. Upon exceeding that amount, large crystalsof forgeable brass appear in the structure. With 6 per cent ofaluminum polyhedric grains only are found, while with 10 percent of aluminum, the grains are found to contain numeroussmall crystals. To sum up, aluminum brasses have a structure similar tothose allo\s containing a larger percentage of zinc. Their colorand behavior when worked lead to the same conclusions. Forinstance, svith 60 per cent copper, 2 per cent aluminum and 38per cent of zinc, the structure is similar to that of a brass con-taining 55 per cent copper and 45 per cent zinc. An additionof
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Keywords: ., bo, bookcentury1800, bookdecade1890, booksubjectiron, bookyear1898
