10 2 Advanced Materials Lab Advanced Materials Lab

제 10장 2원 합금 상태도의 해설 Advanced Materials Lab

Advanced Materials Lab 4

Advanced Materials Lab 5

Advanced Materials Lab 6

가 Advanced Materials Lab 8

Advanced Materials Lab 9

Advanced Materials Lab 10

Ti-Zr계 Cr-Mo계 Au-Ni계 Advanced Materials Lab 11

Equilibrium과 Nonequilibrium cooling 비교 Equilibrium cooling Nonequilibrium cooling n Slow cooling n Faster rate of cooling n Complete diffusion n Incomplete diffusion n Uniform composition n Coring, segregation Advanced Materials Lab 16

Equilibrium Solidification of solid solution alloys Advanced Materials Lab 17

Nonequilibrium Solidification of solid solution alloys : Rapid cooling Advanced Materials Lab 18

Nonequilibrium solidification ü The nonuniform composition produced by nonequilibrium solidification is known as segregation. First solid ü Interdendritic segregation or microsegregation : coring Last liquid Cu Ni ü coring : 편석으로 grain의 내부와 외부의 조성이 경사를 가지며 다르게 갖는 조직. ü the centers of the dendrites : rich in the higher M. P element (first solid) ü the regions between the dendrites : rich in the lower M. P element (last liquid) Advanced Materials Lab 20

ü Microsegregation : 수지상 사이의 짧은 거리에 걸쳐 나타나는 현상으로 용융온도가 낮은 원소가 최종적으로 응고하면서 수지상과 조성차가 발생하는 것. ü Homogenization heat treatment (HHT) : 열을 가하여 확산에너지를 부여함으로써 미세편석 조직 내에서 원소의 확산을 통해 평형상태를 유도하여 균질화하는 열처리. ü heating : below the nonequilibrium solidus → holding ü The nickel atoms in the center of the dendrites diffuse to the interdendritic regions ; copper atoms diffuse in the opposites direction. Advanced Materials Lab 21

ü The Ni atoms in the center of the dendrites diffuse to the interdendritic regions ; Cu atoms diffuse in the opposites direction. First solid Last liquid Cu α 33 Ni α 75 : 75%Ni α 33 : 33%Ni α 33 Advanced Materials Lab 22

20 45 80 Cd-20%Bi Advanced Materials Lab 27

Advanced Materials Lab 33

Advanced Materials Lab 36

L(61. 9%Sn) → α(19%Sn) + β(97. 5%Sn) Advanced Materials Lab 37

Advanced Materials Lab 38

(a)층상공정 (b)봉상공정 (c) 나선상공정 Advanced Materials Lab 39

상온 : (17 -0) / (99. 83 -0) = 17% Si의 최대 고용도 : 1. 65% 99. 83 Advanced Materials Lab 44

Advanced Materials Lab 45

Advanced Materials Lab 47

전율고용체 용해도 곡선 Advanced Materials Lab 48

Advanced Materials Lab 52

포정반응에 의한 조직변화 Advanced Materials Lab 53

t 2 포 정 b 초 정 a 액상 Advanced Materials Lab 54

Advanced Materials Lab 57

Advanced Materials Lab 58

Cr-Cu 모형적 상태도 Negligible solubility : 0. 89 at%Cr at 1077℃ Advanced Materials Lab 61

(Cu + L 1) 편정반응 (Cu + L 2) Cu + Pb Eutectic at 99. 9 wt%Pb Advanced Materials Lab 62

ü Mg : HCP, Pb : FCC ü 금속간화합물 : Mg 2 Pb (Ca. F 2형) 독자적 융점 ü 공정형 상태도를 접합 조합 ü Mg-Mg 2 Pb, Pb-Mg 2 Pb Advanced Materials Lab 65

ü Au : FCC, Bi : 3방정계 ü Au 2 Bi – FCC ü Au + L → Au 2 Bi (포정) ü 33. 3 at%Bi cooling ü 액상선과 교차하는 온도에서 Au정출, 373℃, Au(E), L(F) → 포정반응, Au 2 Bi(P) 생성 Advanced Materials Lab 66