Microstructure Evolution in Cu-Ni-Co-Si-Cr Alloy During Hot Compression by Ce Addition

Area of Science:

• Materials Science
• Metallurgy
• Physical Metallurgy

Background:

• Copper-nickel-silicon (Cu-Ni-Si) alloys are critical for lead frames and vacuum devices due to excellent electrical conductivity and strength.
• Optimizing alloy composition and processing is key to enhancing performance in demanding applications.

Purpose of the Study:

• To investigate the effects of cerium (Ce) addition on the microstructure, texture, and hot deformation behavior of Cu-Ni-Co-Si-Cr alloys.
• To determine the optimal processing parameters for Cu-Ni-Co-Si-Cr-Ce alloys using processing maps.

Main Methods:

• Vacuum induction melting for alloy preparation.
• Hot compression tests using a Gleeble-1500 simulator across a range of temperatures and strain rates.
• Electron backscatter diffraction (EBSD) for texture analysis.
• Microstructural analysis of grain size and precipitate characteristics.

Main Results:

• The <110> fiber component dominated the texture post-compression, with reduced intensity after recrystallization.
• Cu-Ni-Co-Si-Cr-Ce alloy exhibited a lower average misorientation angle (11°) compared to Cu-Ni-Co-Si-Cr (16°).
• Cerium addition resulted in finer average grain size (48 μm vs. 80 μm) and smaller precipitates (27 nm vs. 73 nm).
• The addition of Ce was observed to delay dynamic recrystallization.

Conclusions:

• Cerium addition refines the microstructure and precipitates in Cu-Ni-Co-Si-Cr alloys.
• The modified alloy exhibits improved texture characteristics and delayed dynamic recrystallization, suggesting enhanced mechanical properties.
• Processing maps provide valuable insights for optimizing the thermomechanical processing of these advanced alloys.