Deformation field heterogeneity in punch indentation

Area of Science:

• Materials Science
• Mechanical Engineering
• Solid Mechanics

Background:

• Plastic heterogeneity is crucial for understanding hardness testing and impression-based deformation processing.
• Plane-strain indentation mechanics in metals like copper are complex and require detailed investigation.

Purpose of the Study:

• To investigate the heterogeneous deformation during plane-strain indentation of copper using a flat punch.
• To characterize deformation parameters, microstructure, and crystallographic texture near the indentation.
• To elucidate key features of the indentation process, including deformation modes and material behavior differences.

Main Methods:

• In situ measurement of deformation parameters using high-speed optical imaging of asperity motion.
• Multi-scale analysis of material strength, microstructure, and crystallographic texture.
• Coupling in situ mechanics-based measurements with post-mortem materials characterization.

Main Results:

• Detailed mapping of the plastic deformation field, including a dead-metal zone and regions of intense strain rate (slip lines).
• Quantification of transitions between shear-type and compression-type deformation modes using high-resolution crystallographic texture measurements.
• Demonstrated self-consistency between in situ measurements and post-mortem characterization of the indentation process.

Conclusions:

• The study successfully elucidated salient features of flat punch indentation in copper, providing a comprehensive understanding of plastic heterogeneity.
• Significant differences in indentation mechanics were identified between rigid perfectly plastic and strain-hardening materials.
• The findings offer valuable insights for optimizing hardness testing and impression-based deformation processing methods.