SPS processed TiB2 reinforced Y-α-SiAlON composites: high temperature tribomechanical properties
Himanshu, Soumya Sarkar, Rupa Halder, Mita Biswas Siddhartha Bandyopadhyay, Md. Farooq Wani
Quarterly No. 3, 2019 pages 95-99
DOI:
keywords: Y-α-SiAlON, TiB2, composite, mechanical properties, tribology
abstract Y-α-SiAlON and its composites containing 10 and 20 wt.% titanium diboride (TiB2) were prepared using spark plasma sintering (SPS) at 1750°C for 10 minutes under 50 MPa. Although, the pure Y-α-SiAlON was > 97% dense, the increased TiB2 content resulted in a slight reduction in the relative density of the composites (~2.6% max. at 20 wt.% TiB2). In the presence of TiB2 particulates, the impediment of grain boundary mass transport within the matrix grains might be responsible for such a reduced densification. The addition of TiB2 resulted in a reduced Vickers hardness (HV1), however, the indentation fracture toughness (KIC) of Y-α-SiAlON increased upon an addition of TiB2 up to 20 wt.%. While the HV1 of the 20 wt.% TiB2/ Y-α-SiAlON composite was ~30% lower, the same composite offered around a 28% higher KIC compared to pure Y-α-SiAlON. Unlubricated, reciprocating ball-on-disc experiments up to 500°C in ambient air indicated better wear resistance of the composites compared to pure Y-α-SiAlON up to a 90 N normal load.