Role of Ti3AlC2 MAX phase on characteristics of in-situ synthesized TiAl intermetallics. Part I: sintering and densification

Abstract

Five TiAl–Ti3AlC2 composite samples containing (10, 15, 20, 25 and 30 wt% Ti3AlC2 MAX phase) were prepared by spark plasma sintering technique at 900 °C for 7 min under 40 MPa. For this purpose, metallic titanium and aluminum powders (aiming at the in-situ formation of the TiAl matrix phase) were ball-milled with predetermined contents of Ti3AlC2 MAX phase, which already was synthesized using the same metallic powders as well as graphite flakes. Displacement-time-temperature variations during the heating and sintering steps, displacement rate versus temperature, displacement rate versus time, and densification behavior were studied. Two sharp changes were detected in the diagrams: the first one, ~16 min after the start of the heating process due to the melting of Al, and the second one, after ~35 min because of the sintering progression and the applied final pressure. The highest relative densities were measured for the samples doped with 20 and 25 wt% Ti3AlC2 additives. More Ti3AlC2 addition resulted in decreased relative density because of the agglomeration of MAX phase particles.

Role of Ti3AlC2 MAX phase on characteristics of in-situ synthesized TiAl intermetallics. Part IV: mechanical properties

“…According to the reported relative density of 92.8% for sample 4 (see Ref. [25]) that is higher than that of other samples, higher flexural strength of this sample is logical. The relative density of 90.12% is reported for sample 5 containing 30 wt% Ti 3 AlC 2 , which is the lowest value obtained for this quantity.…”

“…The attained powder mixtures individually filled into the graphite molds, covered by flexible graphite sheet to prevent chemical reaction between the mold and powder mixture. After placing the mold in the SPS device (model: 20T-10), an initial load of ~8 MPa and a preliminary vacuum of 12-15 Pa was applied (details are in [25]). Finally, the synthesis and densification process were carried out through spark plasma sintering technique for 7 min under a pressure of 40 MPa at 900 ºC.…”

“…This paper is 4 th section of series of papers that will study the mechanical characteristics of as-prepared composite samples. The densification behavior, phase evolution, and microstructure development were investigated in pervious 3 papers of these series [25][26][27].…”

“…This part is 4 th section of a series that three sections of them have recently been published. The sintering and densification behavior were discussed in the 1 st section of these series [25], the phase characterization was studied in the 2 nd section of these series [26], and the microstructure investigation was reported in the 3 th section of these series [27]. Table 1 presents the results of the measured Fig.…”

Insights on Spark Plasma Sintering of Magnesium Composites: A Review

“…It helps to fabricate dissimilar materials with a homogenous structure without melting. The TiAl-Ti 3 AlC 2 composite prepared through the SPS process shows a high relative density, but the addition of excessive reinforcement leads to agglomeration of the particle [19,20]. SPS of TiB 2 and the ZrB 2 -SiCw-C f system also shows relatively high density while adding nitrates [21,22].…”