Microstructure and sliding-wear behavior of tungsten-reinforced W-Ni-Si metal-silicide in-situ composites

Abstract

W-Ni-Si metal-silicide-matrix in-situ composites reinforced by tungsten primary grains were fabricated using a water-cooled copper-mold laser-melting furnace by the LASMELT process. Main constitutional phases of the W/W-Ni-Si in-situ composites are the tungsten primary phase, peritectic W 2 Ni 3 Si, and the remaining W 2 Ni 3 Si/Ni 31 Si 12 eutectics, depending on the alloy compositions. The sliding-wear resistance of the W/W-Ni-Si intermetallic composites was evaluated at room temperature and 600°C. Wear mechanisms of the W/W 2 Ni 3 Si in-situ composites were discussed based on morphology observations of the worn surface and wear debris. Results show that the W/W-Ni-Si composites have excellent wear resistance under both room-and high-temperature sliding-wear-test conditions, because of the high yield strength and toughness of the tungsten-reinforcing phase and the high hardness and the covalent-dominated intermetallic atomic bonds of the W 2 Ni 3 Si and Ni 31 Si 12 metal silicides. Tungsten-reinforcing grains played the dominant role in resisting abrasive-wear attacks of microcutting, plowing, and brittle spalling during the sliding-wear process, while the W 2 Ni 3 Si and Ni 31 Si 12 metal silicides are responsible for the excellent adhesive wear resistance.

A wear resistant ductile metal-toughened Cr13Ni5Si2 ternary metal silicide alloy

“…Ni-Cr-Si alloy powders in chemical composition (at.%) of Cr-36.4Ni-11.5Si and with an average particle size ranging from K200 to C320 meshes are selected as the precursor materials for fabricating the g-toughened Cr 13 Ni 5 Si 2 intermetallic alloy with a newly developed laser melting/continuous deposition (LMCD) process in a water-cooled copper-mold laser melting furnace [26][27][28][29], as schematically illustrated in Fig. 1.…”

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

“…Besides Tribaloy, also other Laves phase-based materials were suggested as wear-or corrosion-resistant coatings. Very similar to the Tribaloy composite concept of combining a very hard, highmelting Si-stabilized C14 Laves phase with a more ductile metal or intermetallic phase, a class of wearresistant ternary alloys was developed which are composed of an A 2 B 3 Si-type (i.e., A(B [543,544] or tetragonal W 5 Si 3 [535,545], and Mo(Co 0.75 Si 0.25 ) 2 Laves phase with fcc Co solid solution [546][547][548][549]. The combinations of hard but brittle Laves phase with a toughening second phase such as the metal solid solutions allow the adjustment of properties via variation of the phase contents.…”

Microstructure and tribological properties of NiMo/Mo2Ni3Si intermetallic “in-situ” composites

“…While most of early works focused on the binary metal silicides such as MoSi 2 and its composites [4][5][6][7], some recent studies indicate that ternary metal silicides in the Mo-Ni-Si, W-Ni-Si, Co-Mo-Si, etc. system are a class of promising wear resistance material [10][11][12][13].…”