Static and Dynamic Thermo-Mechanical Behavior of Ti2AlC MAX Phase and Fiber Reinforced Ti2AlC Composites

Abstract

Ti 2 AlC MAX phase samples were processed by using Spark Plasma Sintering from commercially available Ti 2 AlC powder. Static and dynamic loading was performed by Universal Testing Machine and Split Hopkinson Pressure Bar (SHPB) respectively. The SHPB apparatus was modified to investigate the dynamic fracture initiation toughness. High speed photography was used to determine the fracture initiation time and the associated failure load. To widen applications, 20 vol % fiber of NextelTM-610 and NextelTM-720 have been added for the reinforcement of Ti 2 AlC, respectively. The results reveal that the peak compressive failure stress in dynamic conditions decreases with increasing temperatures, from 1,645 MPa at 25 C to 1,210 MPa at 1,200 C. The fracture experiments show that the dynamic fracture toughness is higher than the quasi-static value by approximately 35 %. The fracture toughness decreases with increase in temperature. The post mortem analysis of the fracture surfaces conducted using Scanning Electron Microscopy revealed that kinking along with intergranular cracking and delamination play important role in deformation of Ti 2 AlC. Compared to pure Ti 2 AlC, compressive fracture strength of 20 vol% Ti 2 AlC/720f and Ti 2 AlC/610f composites were enhanced by 39.7 and 32.6 % under static loading. IntroductionThe M n+1 AX n (MAX) phases are a class of nanolayered, machinable, early transition ternary metal carbides and/or nitrides [1]. Because of the structural similarity between MAX phases and their corresponding MX structure, they share lot of properties while some properties are significantly different from their MX counterparts [2,3].Ti 2 AlC is a MAX phase that has attracted a lot of attention as it is machinable, electrically conductive, lightweight and resistant to thermal shock, oxidation and creep [4][5][6][7]. Different methods of fabrication of Ti 2 AlC and its composites for high temperature applications [4,8,9]. The material characterization of MAX phases has been limited to quasi-static loading regimes. The K I values are reported to be in a large range from 4 to 16 MPa m 1/2 are probably attributed to the different grain size, the shape and dimension of the sample, sample impurities, different testing methods, and experimental conditions [10][11][12][13].In this study experiments were conducted to investigate the effect of different strain rate and temperature on the material characteristics. An experimental investigation of the stress strain characteristics of Ti 2 AlC under quasi-static and dynamic loading was conducted at room and elevated temperatures. The peak compressive stress decreases with increasing

Toughening Mechanisms in Nanolayered MAX Phase Ceramics—A Review

“…However, limited work has been performed to investigate the toughening behaviors of fiber- or whisker-reinforced MAX phases due to the high reactivity between the fibers and MAX phase matrix. Most of the work focused on the fabrication of the whisker or fiber/MAX phase composites and the main fibers include SiC fiber [31,32,33], carbon fiber [34] and Al 2 O 3 fiber [35,36]. …”

“…Furthermore, Ti 2 AlC matrix loaded with two type of Al 2 O 3 fibers (20 vol %) was obtained by spark plasma sintering (named as Ti 2 AlC/720f and Ti 2 AlC/610f) [ 36 ]. The fracture experiments and the post-mortem analysis of the fracture surface by SEM revealed that kinking along with intergranular cracking and delamination played an important role in deformation of Ti 2 AlC.…”

Injection Molding and Near-Complete Densification of Monolithic and Al2O3 Fiber-Reinforced Ti2AlC MAX Phase Composites

“…Dash et al reported an increase in the high-temperature creep resistance of Ti 3 SiC 2 when reinforced with SiC (w) [15] and short SiC (f) [16], the former presumably being due to hindered grain boundary sliding. The reinforcement of Ti 2 AlC with Al 2 O 3(f) also resulted in improved thermomechanical properties, with an increase in the compressive fracture strength of up to 39.7% as compared to monolithic Ti 2 AlC [17]. Furthermore, the addition of SiC (f) to Cr 2 AlC led to a 70-80% increase in its wear resistance and a reduction in the friction coefficient up to 20% [18].…”

“…In fact, several studies [15][16][17][18] into fiber and whisker-reinforced MAX phases demonstrated their superior thermomechanical response. Most often, the use of silicon carbide fibers (SiC (f) ), as well as whiskers (SiC (w) ), and alumina fibers (Al 2 O 3(f) ), have been reported.…”

Multifunctional performance of Ti2AlC MAX phase/2D braided alumina fiber laminates

“…In that sense, Ti 2 AlC has been reinforced with 20 vol.% of NextelTM-610 and NextelTM-720 alumina fibers. 16 The compressive failure stress in dynamic conditions decreases with increasing temperature, from 1645 MPa at 25℃ to 1210 MPa at 1200℃. In addition, compressive fracture strength of Ti 2 AlC/720 and Ti 2 AlC/610 composites was enhanced by 39.7% and 32.6% under static loading in comparison with the monolithic Ti 2 AlC.…”