Sequence of Stages in the Microstructure Evolution in Copper under Mild Reciprocating Tribological Loading

Area of Science:

• Tribology
• Materials Science
• Surface Engineering

Background:

• Controlling material surface properties is crucial for minimizing friction and wear in tribological applications.
• Microstructure evolution under tribological load significantly impacts material performance, yet underlying mechanisms remain poorly understood.

Purpose of the Study:

• To investigate the elementary mechanisms of microstructure evolution in high-purity copper under tribological load.
• To correlate microstructural changes with the number of sliding cycles.

Main Methods:

• Reciprocating sliding of a sapphire sphere on high-purity copper.
• Scanning electron microscopy (SEM) and focused ion beam (FIB) microscopy for cross-sectional analysis.
• Analysis of dislocation structures and local orientation changes.

Main Results:

• A tribologically deformed layer formed and grew with increasing sliding cycles.
• Dislocation activity, trace lines, and subgrain boundaries were observed at various depths.
• Evidence suggests dislocation self-organization is a key mechanism for microstructure evolution.

Conclusions:

• Dislocation self-organization is identified as a fundamental process in tribological microstructure evolution.
• Understanding these elementary processes is vital for future tribological contact modeling and material design.