In situ TEM observation of the microstructure characteristics of the vacuum sintering, sub-zero and heat treatments of Vanadis 23 high-speed steel by adding Cr₃C₂–TaC–TiC powders

ABSTRACT

This research added different ratios of chromium carbides, tantalum carbide, and titanium carbide powders to Vanadis 23 high-speed steel powders. The composite powders utilised vacuum sintering at 1230, 1245, 1260, and 1275°C for 1 h, respectively, and the experimental results show that good mechanical properties were obtained by the addition of 0.6 mass% Cr₃C₂–0.2 mass% TaC–0.2 mass% TiC sintered at 1245°C for 1 h. Meanwhile, the apparent porosity was decreased to 0.23%, and the transverse rupture strength and hardness reached 2470.7 MPa and 78.5 HRA, respectively. When optimally sintered Vanadis 23 composites (0.2 T) underwent a series of heat treatments, the transverse rupture strength and hardness values were obviously enhanced to 2693.6 MPa and 84.0 HRA after quenching, and sub-zero and tempering treatments. The EBSD and TEM results confirm that the MC, M₆C, M₇C₃, and M₂₃C₆-type carbides appeared in the 0.2 T specimen after vacuum sintering and sub-zero heat treatments.

KEYWORDS:

• Vanadis 23
• Cr₃C₂–TaC–TiC
• vacuum sintering
• sub-zero
• EBSD
• TEM

Acknowledgements

The authors would like to express their appreciation for VOESTALPINE HIGH PERFORMANCE METALS PACIFIC PTE. LTD. and ASSAB STEELS TAIWAN CO., LTD. Furthermore, thanks to Professor H.C. Lin and Mr. C.Y. Kao of Instrumentation Center, National Taiwan University for EBSD experiments.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research is supported by the Ministry of Science and Technology of the Republic of China (ROC) [grant number MOST 110-2221-E-027-014].

Notes on contributors

Shih-Hsien Chang

Shih-Hsien Chang contibuted to writing and editing. He received an M.S. in Materials Science and Engineering, National Cheng Kung University 1993–1995; a Ph.D. in Materials Science and Engineering, National Cheng Kung University, 2001–2006; He has been working as Professor, Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taiwan, ROC since Feb. 2015.

Chi-Hsien Chang

Chi-Hsien Chang contibuted to data curation and experimental preparation. He received an M.S. in the Institute of Materials Science and Engineering, National Taipei University of Technology, Taiwan, ROC, 2019–2021. He has been working for Taiwan Semiconductor Manufacturing Co., Ltd. (TSMC) Engineer, Taiwan, ROC since 2021.

Kuo-Tsung Huang

Kuo-Tsung Huang contributed to review and editing. He received a Ph.D. in Materials Science and Engineering, National Cheng Kung University, 2001–2007; He has been Lecturer and Principal's Office Chief Secretary since Aug. 2001 in the Department of Auto-Mechanics, National Kangshan Agricultural Industrial Senior High School, Kaohsiung, Taiwan, ROC.