Role of Microstructure on the Potential of MAX and MAB Phases …
19
others. These solids have shown promising properties. Magnetocalorific effect is
observed in Fe 2 AlB 2 [23]. Kota and co-workers [24] have presented a strong case
that MoAlB has excellent potential as high-temperature material as it forms dense
alumina layer on oxidation. MoAlB can also be etched to produce engineered particles due to selective or complete removal of Al from the MoAlB host lattice [25–29].
Recently, Rackl and co-workers [30] synthesized a B-containing MAX phase with
chemistry of Nb 2 SB thus further increasing the diversity of these phases.
The objective is this review is to document the microstructure and properties of
different types of MAX and MAB phase-based composites. In addition, a case study
will be presented to tailor the morphology of Ti 3 AlC 2 particles by etching.
MAX Phase Composites
From the perspective of design of metallic implants for biomaterial applications,
the chemistry of metal-matrix plays a very important role in biomedical applications, for example, Zirconium-Silicon alloys (high strength and low modulus),
Nickel-Titanium alloy (NiTi) (shape memory alloy), 316 stainless steel (corrosion
resistant), Cobalt-Chromium-Molybdenum-alloys (high wear resistant and hardness), Titanium-alloys (corrosion resistant and biocompatibility), Magnesium-alloys
(biocompatible and biodegradable), and Zinc-alloys (biocompatible, biodegradable,
and pro-regeneration) have inherent advantages and disadvantages [31–38]. Different
investigators have designed MAX-based composites with metals like Copper (Cu),
Silver (Ag), Zinc (Zn), Magnesium (Mg), Aluminum (Al), etc. [39–79], MAXceramics [80–86], and MAX-polymer composites [87–97]. In this brief review, I will
focus on MAX-metal and MAX-ceramic composites from structural and biomedical
perspective, for example, wear resistance and mechanical performance.
Figure 1 shows schematics of different types of composites which can be designed
by using MAX phases with different connectivity patterns [98]. As a background,
Newnham and Cross [98] have listed ten different types of connectivity, namely,
0-0, 1-0, 2-0, 3-0, 1-1, 2-1, 3-1, 2-2, 3-2, and 3-3 in diphasic composites. For
example, 3-3 connectivity means both the phases in diphasic composition are forming
interpenetrating network.
MAX phases can act as reinforcement in metal, ceramic, or polymer matrix
composites (type-I, Fig. 1a) to form 3-0 composites where metal or ceramic or
polymer forms the main matrix, and the MAX phases are dispersed in the structure. In type-II composites, MAX phase particulates are bonded with a 3D network
of metallic channel to form 3-0 composites (Fig. 1b). Interpenetrating MAX-metal
composites have 3-3 connectivity (Fig. 1c). The MAX phase matrix can be also reinforced with ceramic additives to form composites with 0-3 connectivity (Type IV,
Fig. 1d). It is also possible to orient MAX phases in different matrices to form 3-0
composites (Type V, Fig. 1e). Composites with multiple layered can be also designed
with 3-0 connectivity (Type VI, Fig. 1f).
19
others. These solids have shown promising properties. Magnetocalorific effect is
observed in Fe 2 AlB 2 [23]. Kota and co-workers [24] have presented a strong case
that MoAlB has excellent potential as high-temperature material as it forms dense
alumina layer on oxidation. MoAlB can also be etched to produce engineered particles due to selective or complete removal of Al from the MoAlB host lattice [25–29].
Recently, Rackl and co-workers [30] synthesized a B-containing MAX phase with
chemistry of Nb 2 SB thus further increasing the diversity of these phases.
The objective is this review is to document the microstructure and properties of
different types of MAX and MAB phase-based composites. In addition, a case study
will be presented to tailor the morphology of Ti 3 AlC 2 particles by etching.
MAX Phase Composites
From the perspective of design of metallic implants for biomaterial applications,
the chemistry of metal-matrix plays a very important role in biomedical applications, for example, Zirconium-Silicon alloys (high strength and low modulus),
Nickel-Titanium alloy (NiTi) (shape memory alloy), 316 stainless steel (corrosion
resistant), Cobalt-Chromium-Molybdenum-alloys (high wear resistant and hardness), Titanium-alloys (corrosion resistant and biocompatibility), Magnesium-alloys
(biocompatible and biodegradable), and Zinc-alloys (biocompatible, biodegradable,
and pro-regeneration) have inherent advantages and disadvantages [31–38]. Different
investigators have designed MAX-based composites with metals like Copper (Cu),
Silver (Ag), Zinc (Zn), Magnesium (Mg), Aluminum (Al), etc. [39–79], MAXceramics [80–86], and MAX-polymer composites [87–97]. In this brief review, I will
focus on MAX-metal and MAX-ceramic composites from structural and biomedical
perspective, for example, wear resistance and mechanical performance.
Figure 1 shows schematics of different types of composites which can be designed
by using MAX phases with different connectivity patterns [98]. As a background,
Newnham and Cross [98] have listed ten different types of connectivity, namely,
0-0, 1-0, 2-0, 3-0, 1-1, 2-1, 3-1, 2-2, 3-2, and 3-3 in diphasic composites. For
example, 3-3 connectivity means both the phases in diphasic composition are forming
interpenetrating network.
MAX phases can act as reinforcement in metal, ceramic, or polymer matrix
composites (type-I, Fig. 1a) to form 3-0 composites where metal or ceramic or
polymer forms the main matrix, and the MAX phases are dispersed in the structure. In type-II composites, MAX phase particulates are bonded with a 3D network
of metallic channel to form 3-0 composites (Fig. 1b). Interpenetrating MAX-metal
composites have 3-3 connectivity (Fig. 1c). The MAX phase matrix can be also reinforced with ceramic additives to form composites with 0-3 connectivity (Type IV,
Fig. 1d). It is also possible to orient MAX phases in different matrices to form 3-0
composites (Type V, Fig. 1e). Composites with multiple layered can be also designed
with 3-0 connectivity (Type VI, Fig. 1f).