Preparation of W-Cu alloy with high density and ultrafine grains by mechanical alloying and high pressure sintering

• Published in: International journal of refractory metals & hard materials Vol. 61; pp. 91 - 97
• Main Authors: Qiu, W.T., Pang, Y., Xiao, Z., Li, Z.
• Format: Journal Article
• Language: English
• Published: Shrewsbury Elsevier Ltd 01-12-2016; Elsevier BV
• Subjects: Alloy powders; ALLOYING; Alloying effects; Alloys; Copper; Densification; Densification mechanism; Density; External pressure; Grain size; GRAIN SIZE AND SHAPE; HARDNESS; Heating; HIGH PRESSURE; High pressure sintering; Hot pressing; Mechanical alloying; MICROSTRUCTURES; Nanostructure; Pressure sintering; Sintered compacts; SINTERING; Sintering (powder metallurgy); Temperature effects; Theoretical density; Tungsten base alloys; W-Cu alloy; High pressure sintering; W-Cu alloy; Densification mechanism; Mechanical alloying
• ISSN: 0263-4368; 2213-3917
• DOI: 10.1016/j.ijrmhm.2016.07.013

W-20 wt%Cu alloy, with a high sintering density of 99.2% theoretical density (%TD), ultrafine grain size of 500nm, and hardness of 310HV, was fabricated by mechanical alloying and high pressure sintering (HPS). The changes of morphology and structural evolution of W-Cu powders during mechanical alloying process were observed and studied, and the effects of temperature and pressure on the density of sintered compacts were studied. Results showed that nanostructured (NS) mechanical alloyed (MA) W-Cu powders were obtained after a 40h milling at a milling speed of 400rpm, and the W-Cu alloy had nanocrystalline structure and shape retention with nearly full densification when the HPS of NS MA W-Cu powders was carried out at 1050°C with a pressure of 40MPa. The densification behavior of NS MA W-Cu powders during HPS was also studied, including a nanosintering within the MA powders during heating and a global rearrangement and sintering when an external pressure was applied.
•W-Cu alloy with high density and ultra-fine W grains was obtained.•The nanostructured W-Cu powders were obtained after 40h milling.•The effects of temperature and pressure on the density of W-Cu alloy were studied.•The densification behavior of NS MA W-Cu powders during HPS was discussed.