| Title |
The Microstructures and Mechanical Properties of Extruded Bars of Rapidly solidified Fe - 3.6% C - si Alloy Powders |
| Authors |
여동훈(D . H . Yeo); 김동익(D . I . Kim); 나형용(H . Y . Ra) |
| Abstract |
In this study, Fe-3.6%C-Si alloy powders were made using high pressure gas atomizer and ribbons by melt spinner. The solidified structure and annealed structure of powders and/or ribbons were studied, then mechanical properties of its exturded bars were discussed. The solidified structure of coarse powders about 100㎛ was the mixture of ledebrite eutectic and dendrite, when Si content is 1∼2%, dendrite proved to be austenite and when 3∼4% to be cementite. The solidified structure of fine powders(20 ㎛) and ribbons was mainly ledebrite eutectic. The hardness of powders recorded 1000∼1500MVH(㎏/㎟) and increased as Si contents increased. After annealing, hardness decreased to 200∼300 MVH because graphite precipitated in powders. After extrusion, the matrix transformed to ferrite and graphite precipitated uniformly at prior particle boundary or inside of powders. The tensile strength increased with increasing extrusion rate and reached 65∼75㎏/㎟ when extrusion rate was 13. Toughness was 7∼7.5㎏·m/㎠ and hardness was 100∼110HR_8. |