Effects of heat treatment system and Cu content on the microstructure and mechanical properties of two conventionally cast Al-Cu-Mn alloys were investigated. It is found that after treatment at proper temperatures, including 525 ℃×16 h+170 ℃×8 h for Cu2.8 alloy, 525 ℃×16 h+170 ℃×14 h for Cu5.7 alloy, the Cu2.8 alloy and Cu5.7 alloy have their tensile strength up to 209.76 MPa and 349.15 MPa respectively, and yield strength reaching 107.15 MPa and 216.21 MPa correspondingly. The detailed exploration of precipitation behavior of the alloy after aging indicates that Cu content brings an important influence to the precipitation behavior. The precipitation of the T phase leads to depletion of Cu atoms in low-Cu alloy during solid solution process. The θ′ phases only adhere near the T phase, and dispersed θ″ phases are only precipitated in the high-Cu alloy, which contribute mainly to higher strength of high-Cu alloy.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |