Structural, physical and mechanical properties of Ti3(Al1−xSix)C2 solid solution with x=0–1

Abstract

A series of high-purity Ti 3 (Al 1-x Si x)C 2 solid solutions with 0<x<1 were reaction sintered from Ti, Si, Al and TiC powders using Pulsed Electric Current Sintering (PECS) 1 .The a-lattice parameter of all sintered solid solutions remains constant at approximately 0.307 nm, while the c-lattice parameter decreases from 1.858 nm to 1.763 nmwith increasing amount of Si.The specific heat capacity of Ti 3 Al 0. 6Si 0.4 C 2 was found to be comparable to that of end-member MAX phases, namely Ti 3 AlC 2 and Ti 3 SiC 2, while its coefficient of thermal expansion (CTE)was lowerthan that of the end members. Both Young's and shear moduli increase with increasing amount of Si. Vickers hardness (H v) measurements demonstrate significant hardening effect in Ti 3 (Al 1-x Si x)C 2 solid solutions regardless of the grain size , i.e. it changes from 4.1±0.14 GPa of Ti 3 AlC 2 and 4.2±0.37 GPa of Ti 3 SiC 2 , up to 5.6±0.2 GPa for Ti 3 (Al 0.4 Si 0.6)C 2. At room temperature, the strengthening effect was found to be marginal in the fine grained structure, as 1 This method is commonly but inaccurately referred to as Spark Plasma Sintering (SPS).

The synthesis and mechanical properties of high pure Ti2Al(Sn)C solid solution

“…During the sintering process of Ti 2 AlC, it is difficult to avoid the Ti 3 AlC 2 phase in reality, the formation of Ti 2 AlC or Ti 3 AlC 2 in the Ti‐Al‐C/TiC system has been extensively studied, similar situations were demonstrated in references and . In Ti‐Al‐C/TiC system, the existence of liquid phases promoted the growth of Ti 2 AlC . Ti‐Al liquid phases were formed firstly at temperatures around the melting point of Al, as described by reaction .…”

“…Observing that as Sn content increases in Ti 2 Al 1− x Sn x C solid solution, the lattice parameter a increases slowly and locates between that of Ti 2 AlC and Ti 2 SnC, meanwhile, the value of lattice parameter c is basically stable after the addition of tin is 0.5 mole. The behavior is similar to that of Ti 3 Al(Sn)C 2 in previous studies, but is different from that of Ti 3 Al(Si)C 2 , the lattice parameter a in Ti 3 Al(Si)C 2 shows nearly no changes while the lattice parameter c decreases linearly with increasing Si content.…”

“…Previous studies have shown that the addition of solid solution elements have obvious strengthening effect on MAX phases. Such as Ti 3 AlSnC 2 and Ti 3 AlSiC 2, the substitutions of Sn and Si elements make the flexural strength and micro‐hardness of Ti 3 AlSnC 2 and Ti 3 AlSiC 2 improved. However, in some other MAX phase solid solutions, such as Ti 3 Si(Ge)C 2 , Cr 2 Al(Si)C and (Ti,Nb) 2 AlC, no solid solution strengthening or hardening effect were detected.…”

Does aluminum play well with others? Intrinsic Al-A alloying behavior in 211/312 MAX phases

“…This is a significant result that indicates that one cannot glean trends for possible doping strategies by simply looking into the types of interactions that occur between A-type species in bulk binary crystal systems. The almost ideality of Al-Si interactions is supported by the recent synthesis of Ti2(Al,Si)C over the entire composition range [20]. A more detailed analysis of the electronic structure of this system close to the Fermi level would be necessary to elucidate the nature of the (lack of) chemical interactions within the A layer in this system, but this is beyond the scope of this work.…”

“…Yu et al [19] investigated Cr 2 (Al,Si)C solid solutions and concluded that partial substitution of Al for Si had positive effects on the strength of the material. Gao et al [20] recently investigated solid solutions in the Ti 3 (Al 1−x Si x )C 2 system and found not only stable solid solutions through the entire composition range but also significant solid-solution hardening without compromising oxidation resistance. Finally, Horlait et al [16] provided the first evidence for Bi-containing MAX phases (Zr 2 Al 1−x Bi x C with x ∼ 0.58), while Lapauw recently reported the synthesis of Zr 2 AlC, albeit in a two-phase microstructure with ZrC being the secondary phase [21].…”