JAMPT engaged exclusive license for the new Al alloy for AM developed by Koiwai, by Toyo Aluminium, Kyushu University and Chiba Institute of Technology to utilize it in the various field of industry through AM process.
Al-10%Si-0.4%Mg alloy is famous alloy for AM process. This alloy shows about 450MPa ultimate tensile strength at conditions that the base plate is not preheated. But the shape of this alloy product fabricated without preheating of base plate is distorted. So it is necessary to keep the temperature near 200℃ to fabricate no distorted product . As the result, the ultimate tensile strength of the alloy is down to about 300MPa. The decrease of the ultimate tensile strength is caused by over aging of Mg-Si precipitation at near 200℃.
The newly developed Mn-added alloy shows high tensile strength of 7000 series alloy (“Duralumin”) level of about 400~500 MPa without generating strain by selective laser melting. Moreover, T6(*) heat treatment is not adopted.
| Chemical component of high tensile strength Al alloy at room temperature(%) | |
|---|---|
| Si | 7 |
| Mg | 0.7 |
| Fe | ≦0.3 |
| Mn | 1.5 |
| AI | bal. |
AC8A(Al-12%Si-1%Cu-1%Mg-1%Ni, similar alloy AA336.0, AA339.0) is famous casting alloy for heat-resistant parts, such as piston. But this alloy fabricated by AM shows about 80MPa or less at 300℃. This value is different from that of AC8A by casting process.
High temperature strength at 300℃ is increased by adding transition metal. The value improved 1.5 to 2 times that of casting alloys.
The newly developed Fe-added alloy shows high tensile strength by selective laser melting. The desirable addition amount of Fe is about 2% to prevent cracks of AM product. Moreover, T6(*) heat treatment is not adopted to obtain the high temperature strength.
| Chemical component of heat resistant Al alloy(%) | |
|---|---|
| Si | 10 |
| Cu | 1 |
| Mg | 1 |
| Ni | 1 |
| Fe | 2 |
| AI | bal. |
(*) T6: Solution treatment ⇒ Water quenching ⇒ Aging
