Ultrashort Sintering and Near Net Shaping of Zr-Based AMZ4 Bulk Metallic Glass

Abstract

The GeniCore Upgraded Field Assisted Sintering Technology U-FAST was applied to the sintering of a commercial Zr-based bulk metallic glass powder AMZ4. The XRD, SEM and DSC analysis of the sintered compacts showed the benefit of the U-FAST method as an enabler for the production of fully amorphous samples with 100% relative density when sintering at 420 °C/480 s (693 K/480 s) and 440 °C/ 60 s (713 K/480 s). The hardness values for fully amorphous samples, over HV1 519, surpass cast materials and 1625 MPa compressive strengths are comparable to commercial cast products. The advantage of the U-FAST technology in this work is attributed to the high heating and cooling rates inherent to ultra-short pulses, which allow to maintain metastable structures and achieve better temperature control during the process. Increasing sintering temperature and time led to the crystallization of the materials. The geometry and material of the dies and punch determine the thermal inertia and pressure distribution inside the compacts, thus affecting the properties of the near net shape NNS compacts made using the U-FAST device.

Study of Bulk Amorphous and Nanocrystalline Alloys Fabricated by High-Sphericity Fe84Si7B5C2Cr2 Amorphous Powders at Different Spark-Plasma-Sintering Temperatures

“…Based on other studies on crystallization during SPS [ 5 , 14 , 22 , 26 ], the reasons for the occurrence of crystallization in the T x1 in this study are as follows: Unlike conventional heating methods, SPS generates Joule heat directly inside the compacts, which can result in the graphite-die temperature measured by the thermocouple being lower than the actual internal temperature of the compacts. The electrical resistance in the particle-contact area is large, generating a large amount of Joule heat and local overheating.…”

“…5 bulk amorphous by SPS and studied the influence of loading pressure on the densification degree and properties of bulk amorphous alloys [ 13 ]. Zrodowski et al prepared a completely Zr-based amorphous alloy with a relative density of 100% by SPS and proved through experiments that SPS could fabricate bulk amorphous alloys with complex shapes [ 14 ]. Moravcikova-Gouvea et al prepared Al 0 .…”