1. Iron, manganese and nickel are the main added elements in aluminum bronze. Therefore, complex aluminum bronzes include Cu-Al-Fe, Cu-Al-Mn, Cu-Al-Fe-Mn, Cu-AlFe-Ni and Cu-Al-Fe
Mn-Ni system.
Adding iron to Cu-Al alloy inhibits the decomposition of β→α+γ2 and prevents embrittlement caused by spontaneous annealing. In addition, adding a certain amount of iron can form fine FeAl3 particles, which can be used as α
The non-spontaneous crystal nuclei refine the α grains in the as-cast structure.
2. The solubility of manganese in Cu-Al alloy is large, which can cause solid solution strengthening. More importantly, it can also inhibit the phenomenon of spontaneous annealing. The addition of manganese has no effect on the microstructure of aluminum bronze
significant impact.
3. The main function of nickel is to improve the mechanical properties, thermal strength and corrosion resistance of the alloy. Nickel is mainly added to aluminum-iron bronze, and besides being dissolved into solid solution (α and β), it can also form K phase.
The phase is a Ni-Fe-Al compound with an ordered body-centered cubic lattice, and the structure is similar to NiAl and FeAl. The content and mutual ratio of aluminum, iron and nickel in the alloy, as well as the heat treatment conditions of the alloy
Both affect the K phase precipitation morphology and alloy properties. When the nickel content is greater than the iron content, the K phase is in the form of lamellar sheets, and when the nickel content is less than the iron content, the K phase will be precipitated in the form of blocks. Only when iron and nickel contain
When the amount is roughly equal, the K phase is precipitated in fine grains, which is beneficial to the mechanical properties of the alloy.
4. The structure of aluminum bronze is easy to identify. Generally, it can be corroded by reagents such as ferric chloride hydrochloric acid aqueous solution or ferric chloride hydrochloric acid alcohol solution. The α phase is white and bright, and the β phase (or eutectoid) is
grey. The iron-containing phase is bright gray particles, if it is very small, it is difficult to distinguish. The K phase is also bright gray. The organization formed by the intersection of martensite has obvious needle-like characteristics.