Abstract:
Aims: Pure titanium wire was forged in dry and cold without galling to β-SiC coating dies up to the reduction of thickness by 35%.
Methods: β-SiC coated SiC die and punch were employed for forging of the titanium wire to a triangular bar. SEM-EDX and Raman spectroscopy were employed for characterization on the contact interface between SiC coating punch and titanium work after continuous cold dry forging.
Results: SEM-EDX analysis on the contact interface proved that no galling took place during this cold forging. Thin titanium oxide film was formed on this contact interface. Low frictional state was preserved during the flattening process from a circular wire to a triangular bar. Raman spectroscopy proved that unbound carbon could isolate from β-SiC coating at the high stressed contact interface.
Conclusions: The pure titanium circular wire was forged into triangular bar without metallic titanium transfer onto β-SiC coating punch and die. Titanium oxide debris particles deposit onto the β-SiC coating punch surface and form a thin tribofilm onto the punch surface in the radial direction from the center of contact interface. Carbon agglomerates at this high stressed zone and works as a solid lubricant to hinder the adhesion of titanium fresh surface to β-SiC coating die surfaces.
Acknowledgements: The authors would like to express their gratitude to Mr. S. Kurozumi (Nano-Coat Film, LLC.) Mr. T. Yoshino (Komatsu-Seiki Kosakusho, Co., Ltd.) for their help in experiment.

Biography: Dr. Tatsuhiko Aizawa received PhD from The University of Tokyo in 1980. He became a research associate, Institute of Aerospace and Aeronautics in 1980, a lecturer in 1985, an associate professor in 1986 and a professor in 1996 till 2004 at the University of Tokyo. After the research professor in the University of Toronto from 2005 to 2008, he has been working as a professor in SIT from 2009 till now. His research interests include the micro-manufacturing, the innovations in manufacturing and materials processing, and, the materials science and engineering.

He has published over 500 papers in Japanese and International Journals and over 50 patents. He has received lots of awards from academic societies including the Distinguished Achievement Award, Japan Institute of Metals, 2011 and, the Gold Medal, 2017, the Achievement Award, 2019, Japan Society of Technology of Plasticity, respectively.