In the present study, we investigate the effects of milling time and the addition of a process control agent (PCA) on the austenite stability of a nanocrystalline Fe-7%Mn alloy by XRD analysis and micrograph observation. Nanocrystalline Fe-7%Mn alloys samples are successfully fabricated by spark plasma sintering. The crystallite size of ball-milled powder and the volume fraction of austenite in the sintered sample are calculated using XRD analysis. Changes in the shape and structure of alloyed powder according to milling conditions are observed through FE-SEM. It is found that the crystallite size is reduced with increasing milling time and amount of PCA addition due to the variation in the balance between the cold-welding and fracturing processes. As a result, the austenite stability increased, resulting in an exceptionally high volume fraction of austenite retained at room temperature.

Abstract
 1. 서 론
 2. 실험 방법
 3. 결과 및 고찰
 4. 결 론
 References

• 오승진(전북대학교 신소재공학부) | Seung-Jin Oh
• 손인진(전북대학교 신소재공학부) | In-Jin Shon
• 이석재(전북대학교 신소재공학부) | Seok-Jae Lee Corresponding Author