Influence of reinforcement and processing on steel-based composites: Microstructure and mechanical response

Impression creep behaviour of TiB2 particles reinforced steel matrix composites

“…The microstructural examination of unreinforced steel (Figure 1a) shows the presence of single phase with little amount of porosity. In line with our previous work [25], the total amount of porosity was observed in the range of 8-11%. Similar observation of high level of porosity due to an increase of TiB 2 content was also reported for spark plasma processed steel matrix composites [26].…”

“…Figure 1 presents the FESEM micrographs of unreinforced steel and steel reinforced with 2 and 4 vol.-% TiB 2 hot pressed samples. The dark region corresponds to TiB 2 while the light region corresponds to steel matrix as reported in our previous work [25]. The microstructural examination of unreinforced steel (Figure 1a) shows the presence of single phase with little amount of porosity.…”

“…In addition, the strength of the composites increases due to a decrease in inter particle spacing with an increase in the amount of reinforcement particles. In our previous work [25], we observed a decrease in the value of inter particle spacing from 3.85 to 2.59 µm with an increase in titanium diboride from 2 to 4 vol.-%. Consequently, with a decrease in inter particle spacing, barriers to dislocation motion increase leading to improvement in strength and load-bearing capacity of the composites.…”

“…Mulhearn and Tabor [32] reported a decrease in indentation depth with an increase in hardness during indentation to cause plastic deformation. Hence, observation of minimum indentation depth of 4 vol.-% TiB 2 steel matrix composite as compared to other samples can be attributed to the highest hardness of the sample among others [25]. The increase in TiB 2 particles at grain boundaries can represent an effective barrier to dislocation motion and also lead to reduce grain boundary sliding.…”

Influence of ZrB2 on Microstructure and Properties of Steel Matrix Composites Prepared by Spark Plasma Sintering

“…The introduction of hard ceramic particles into the steel matrix improves the mechanical and tribological properties of such composites [19,20]. The ceramic particles used most commonly as a reinforcement of the steel matrix are oxides [21][22][23], carbides [24,25], nitrides [26] and borides [10,[27][28][29]. Most research concerns optimization of the sintering process, determination of the impact of different sintering conditions and reinforcing phase content on the physical (density, porosity), mechanical and microstructural properties of composites.…”