Raytron Technical Review RESEARCH ARTICLE WP-01-08

Heat Treatment: Optimizing Bimetallic Properties

Q: How to determine annealing temperature for bimetallic conductors?

Annealing temperature needs to consider recrystallization temperatures of both metals. CCA annealing temperature should be above aluminum's recrystallization temperature (150-250°C) but below copper's (200-300°C), typically 250-350°C. Excessive temperature leads to excessive IMC growth.

Q: How does heat treatment affect conductivity?

Annealing can eliminate lattice defects and improve conductivity. Conductivity is lower in work-hardened condition and can recover to near theoretical values after annealing. However, excessive IMC growth increases interface resistance and reduces overall conductivity.

Q: How to choose heat treatment type?

Full annealing: choose when maximum ductility and softness are needed; Partial annealing: choose when balance of moderate strength and ductility is needed; Stress relief annealing: choose when maintaining strength while reducing internal stress is needed. Determine based on application requirements.

RAYTRON技术团队¹ *

¹RAYTRON集团技术研究中心, 中国

^*Corresponding author

Received: 2025年12月 Accepted: 2026年2月 Published: 2026年3月

DOI: 10.1234/raytron.2026.WP-01-08

Abstract

热处理是控制双金属导体性能的关键工艺。本白皮书研究退火、固溶处理和时效处理对双金属导体性能的影响。我们分析热处理过程中的组织变化、界面演变和性能优化，为不同应用提供热处理工艺指南。

Key Findings

Annealing Restores Ductility Annealing eliminates work hardening through recovery and recrystallization, restoring material ductility. Annealing temperature is 250-350°C for CCA, 400-500°C for CCS, 350-450°C for NCC, with duration of 30-60 minutes.
Interface Evolution Needs Control During heat treatment, interface undergoes diffusion and intermetallic compound growth. CCA requires control of annealing temperature and time to avoid excessive IMC thickness (<3μm). NCC has better interface stability due to solid solution formation.
Properties are Customizable By selecting different heat treatment processes, mechanical and electrical properties of bimetallic conductors can be customized. Full annealing yields softest condition, partial annealing yields moderate strength, stress relief annealing maintains strength while reducing internal stress.
Atmosphere Control is Important Heat treatment requires protective atmosphere (e.g., N₂, Ar) to prevent oxidation and surface contamination. For CCA, inert atmosphere prevents aluminum oxidation; for NCC, prevents nickel surface oxidation affecting weldability.

Keywords

热处理;退火;固溶处理;时效;再结晶;界面演变

1. 引言

热处理是控制双金属导体力学性能和导电性能的关键工艺。

2. 退火工艺

创建退火温度对性能的影响曲线

MEDIA TODO

Figure Fig. 1 退火温度对性能的影响

创建再结晶过程示意图

MEDIA TODO

Figure Fig. 2 再结晶过程示意图

3. 固溶处理

4. 时效处理

5. 界面演变

界面演变SEM照片

MEDIA TODO

Figure Fig. 3 界面演变SEM照片

6. 结论

Frequently Asked Questions

How to determine annealing temperature for bimetallic conductors?

Annealing temperature needs to consider recrystallization temperatures of both metals. CCA annealing temperature should be above aluminum's recrystallization temperature (150-250°C) but below copper's (200-300°C), typically 250-350°C. Excessive temperature leads to excessive IMC growth.

How does heat treatment affect conductivity?

Annealing can eliminate lattice defects and improve conductivity. Conductivity is lower in work-hardened condition and can recover to near theoretical values after annealing. However, excessive IMC growth increases interface resistance and reduces overall conductivity.

How to choose heat treatment type?

Full annealing: choose when maximum ductility and softness are needed; Partial annealing: choose when balance of moderate strength and ductility is needed; Stress relief annealing: choose when maintaining strength while reducing internal stress is needed. Determine based on application requirements.

Figures

创建退火温度对性能的影响曲线

Fig. 1 退火温度对性能的影响

创建再结晶过程示意图

Fig. 2 再结晶过程示意图

界面演变SEM照片

Fig. 3 界面演变SEM照片

Tables

Table 1 退火参数

材料	温度 (°C)	时间 (min)	气氛
CCA	250-350	30-60	N₂
CCS	400-500	30-60	N₂
NCC	350-450	30-60	N₂

Table 2 热处理类型选择

目标	处理类型	适用材料
软化	完全退火	CCA, CCS
强化	时效处理	CCAA
消除应力	低温退火	所有

References

ASM International Heat Treating Handbook ASM (2020)

Authoritative References

ASTM International IEC (International Electrotechnical Commission) ISO (International Organization for Standardization) SAE International IEEE

Heat Treatment: Optimizing Bimetallic Properties

1. 引言

2. 退火工艺

3. 固溶处理

4. 时效处理

5. 界面演变

6. 结论

Frequently Asked Questions

How to determine annealing temperature for bimetallic conductors?

How does heat treatment affect conductivity?

How to choose heat treatment type?

Figures

Tables

References

Authoritative References

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