| Title |
A Study on Mechanical Properties of AZ91 Magnesium Alloy Machined Chips by Hot Extrusion |
| Authors |
이두면(Doo Myun Lee); 이지환(Chi Hwan Lee) |
| Abstract |
AZ91 magnesium alloy machined chips were hot extruded at 300∼380℃ temperature range under the extrusion ratio of 25 : 1 and die angle(2θ) of 60˚. The microstructure and mechanical properties of the extruded chips were studied in order to find good extrusion properties. As-received ingot and extruded ingot were used as reference materials. Also, heat-treatment was carried out for all the extruded bars. The microstructure of the extruded chips showed fine equiaxed grains due to dynamic recrystallization during hot extrusion and the chips were perfectly bonded. The age-hardening behaviors of the extruded chips and the extruded ingot showed the highest peak of hardness at aging time of 26∼40 hours at 170℃. The tensile strength and elongation of the extruded chips at room temperature were 330 MPa and 10%, respectively. These value were approximately the same as those of the extruded ingot. In the effect of heat-treatment, the elongation of heat-treated extruded bars was founded to be less than that of as-extruded bars. This may be due to the grain-coarsening induced to softening during solution treatment. |