Effects of annealing temperature on the microstructure and mechanical properties through thickness of a Cu-3.0Ni- 0.7Si alloy processed by differential speed rolling are investigated in detail. The copper alloy with a thickness of 3 mm is rolled to a 50 % reduction at ambient temperature without lubricant and subsequently annealed for 0.5 h at 200-900 oC. The microstructure of the copper alloy after annealing is different in the thickness direction depending on the amount of the shear and compressive strain introduced by the rolling; the recrystallization occurs first in the upper roll side and center regions which are largely shear-deformed. The complete recrystallization occurs at an annealing temperature of 800 oC. The grain size after the complete recrystallization is finer than that of the conventional rolling. The hardness distribution of the specimens annealed at 500-700 oC is not uniform in the thickness direction due to partial recrystallization. This ununiformity of hardness corresponds well to the amount of shear strain in the thickness direction. The average hardness and ultimate tensile strength has the maximum values of 250 Hv and 450 Mpa, respectively, in the specimen annealed at 400 oC. It is considered that the complex mode of strain introduced by rolling directly affects the microstructure and the mechanical properties of the annealed specimens.

Abstract
 1. 서 론
 2. 실험 방법
  2.1 이속압연 및 어닐링
 3. 결과 및 고찰
  3.1 이속압연에 의해 도입된 두께방향으로의 변형량의크기
  3.2 어닐링에 따른 두께방향으로의 미세조직 변화
  3.3 어닐링에 따른 기계적 성질의 변화
 4. 결 론
 References

• 이성희(국립목포대학교 신소재공학과) | Seong-Hee Lee (Department of Advanced Materials Science and Engineering, Mokpo National University) Corresponding author