Metal material sintering densification and grain size control method

US11673196B2 · kind B2 · utility

Assignee

• University of Science and Technology Beijing · CN

Inventors

• Lin Zhang · Tongxiang, CN
• Xuanhui Qu · Beijing, CN
• Xingyu LI · Beijing, CN
• Mingli Qin · Beijing, CN
• Yanhao Dong · Beijing, CN
• Ju Li · Weston, US
• Guanghua Wang · Clifton Park, US
• Ying Long · Beijing, CN
• Wei Zhong · Pullman, US

Key dates

• Filing date: Feb 18, 2020
• Grant date: Jun 13, 2023
• Expiry date: Sep 25, 2041

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B22F2999/00
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A method to achieve full densification and grain size control for sintering metal materials, wherein raw material powder is deagglomerated to obtain deagglomerated powder with dispersion. The deagglomerated powder is granulated by spray granulation. The granulated particles are processed by high-pressure die pressing and cold isostatic pressing. The powder compact is sintered by two-step pressureless sintering. The first step is to heat up the powder compact to a higher temperature and hold for a short time to obtain 75-85% theoretical density; the second step is to cool down powder compact to a lower temperature and hold for a long time. The two-step sintering can decrease the sintering temperature, so that the powder compact can be densified at a lower temperature. Thus, the obtained refractory metal product is densified, with ultrafine grains, uniform grain size distribution, and outstanding mechanical properties.