Interfacial reaction-controlled reprecipitation of W atoms in liquid matrix phase during the sintering of W-8 pct Mo-7 pct Ni-3 pct Fe

Abstract

Microstructural evolution and variation in phase composition of W-8 pct Mo-7 pct Ni-3 pct Fe alloy were investigated with respect to various isothermal holding times, ranging from 5 to 240 minutes, at a sintering temperature of 1480 ЊC. Mass transfer was found to proceed actively in both the liquid matrix phase and the tungsten-based solid phase during the initial stage of the isothermal hold. Formation of large jagged grains was found to be a result of excessive interdiffusion between molybdenum and tungsten. The jagged grains gradually developed into spheroidal grains with the reprecipitation of supersaturated tungsten atoms in the liquid matrix phase, which also resulted in crystallization of the matrix phase with less lattice dilation during cooling. Based on model fitting, reprecipitation of tungsten atoms from the liquid matrix phase to grains is proposed to be controlled by a first-order interfacial reaction.

Review: liquid phase sintering

“…Grain growth inhibitors slow interfacial reaction events. The most effective inhibitors reduce the number of reaction sites, leading to the emergence of flat-faced grains or core-rim grains, where the chemistry changes from the outside to the inside [133][134][135][136]. In diffusion-controlled growth, the grains remain rounded with an abundance of atomic steps, so there is no limitation from the population of interfacial sites available for dissolution or precipitation [9,131,137].…”

Ultrasound-assisted regio- and stereoselective synthesis of bis-[1′,4′-diaryl-1-oxo-spiro-benzosuberane-2,5′-pyrazoline] derivatives via 1,3-dipolar cycloaddition

“…6,7 1,3-Dipolar cycloaddition is one of the most valuable synthetic routes for the synthesis of vemembered heterocycles. 8,9 Spiropyrazoline derivatives are involved in several pharmaceutical agents, such as antiviral and antibacterial activities, 10,11 anti-cancer agents, 12 as well as acetyl-CoA carboxylase inhibiting activities. 13 Benzosuberone moiety (6,7,8,9-tetrahydrobenzo-cyclohepten-5-one) was found in variety of biologically active compounds that proved to have anti-cancer, [14][15][16] anti-proliferative 17 and antiangiogenic agents 18,19 as well as human aminopeptidase 20,21 and acetylcholinesterase inhibiting activities.…”

The Effects of Molybdenum Content on the Dynamic Properties of Tungsten-Based Heavy Alloys

“…In addition, the Mo element has significant influences on the microstructures of W heavy alloys such as contiguity, grain shape, interfacial phase, etc. [3][4][5][6][7]. Current studies on the effects of Mo on the mechanical properties of W-Mo-Ni-Fe alloys are based on quasi-static tests and analyses.…”