Characteristics of the Nial/Ni3al Matrix Composite With Tib2 Particles Fabricated By High Pressure – High Temperature Sintering

Abstract

The article presents the results of tests carried out on the manufactured composite materials based on a two-phase NiAl/Ni 3 Al matrix, which was enriched with the addition of TiB 2 ceramic particles added in an amount of 4 and 7 vol%. The resulting mixtures were sintered by the High Pressure High Temperature (HP-HT) process. The results were compared to the results obtained for the sole matrix material produced under the same conditions. It has been shown that, at a lower density, the addition of reinforcing particles increases the composite hardness, Young's modulus and resistance to frictional wear. However, higher addition of TiB 2 (7 vol%) was observed to yield less satisfactory results, and despite higher hardness and lower density caused a decrease in other properties tested. The produced materials were characterized by a compact and highly differentiated microstructure free from any noticeable cracks and pores.

Effect of Reactive SPS on the Microstructure and Properties of a Dual-Phase Ni-Al Intermetallic Compound and Ni-Al-TiB2 Composite

“…The results of the measurements of density and porosity ( Figure 6 a) did not reveal any significant differences in these properties, which would depend on the matrix structure (relative density above 99% for both types of sinters). The results of the measurements of HV1 hardness ( Figure 6 b) and Young’s modulus ( Figure 6 c), as well as a comparison of these results with studies carried out by other authors [ 39 , 40 ] and with our own research [ 29 , 41 ], have led to the conclusion that the cause of the differences should be sought in the addition of TiB 2 hard particles and related hardening effect rather than in the different matrix microstructures observed in these sinters.…”

“…The formation of slippery oxides in the friction process can explain the observed reduced wear. Making a comparison with our previous research [29], where the dual-phase matrix was produced before the sintering process, with the same test parameters, similar results of the wear behaviour were obtained. A slight difference in the results of the friction coefficient and the wear coefficient (specific wear rate) may result from the different process of the manufacture of the dual-phase matrix and/or from the use of a different HPHT sintering method (7.5 GPa, 1779 K).…”

“…As a result of the research, a high relative density was obtained, similar to the relative density obtained in the case of high-pressure high-temperature (HPHT) sintering [ 29 ]. The relative density was in both cases above 99%, which means that it was higher than in the SPS tests where it was 98%, but the reacted powder was used then [ 41 ].…”

“…In previous studies [ 29 ], it has been observed that the addition of TiB 2 to the two-phase NiAl/Ni 3 Al matrix increases the composite strength and tribological properties. However, in previous studies, other powders (commercial, produced after the exothermic reaction), another sintering method—high-pressure high-temperature (HPHT) and other sintering parameters (T = 1779 K and 7.5 GPa) were used.…”

Production of Mo2NiB2 Based Hard Alloys by Self-Propagating High-Temperature Synthesis

“…As expected in alloy F, after a certain value of Ni, the hardness value decreased due to increasing matrix/reinforcement ratio in the as-cast alloys. It can be concluded that the reinforcing boride phases improved the hardness values of the composites with NixAl (x=1,3) phase matrix, as also reported in the literature [22].…”