The Flexural Strength and Fracture Toughness of TC4-Based Laminated Composites Reinforced with Ti Aluminide and Carbide
TiC–Ti–Al mixed powders and TC4 titanium alloy foils were overlapped layer-by-layer in the graphite die. The TC4-based laminated composite sheets reinforced by Ti aluminide and carbide were successfully fabricated via spark plasma sintering (SPS) at 1100 °C with a well-bonded interface. The composite layers were mainly composed of TiAl, Ti3Al, Ti2AlC, and Ti3AlC2 phases. The carbides particles distributed in the matrix played an important role in the deflection of cracks and the passivation of microcracks. TC4 titanium alloy layers had an obvious effect on the stress distribution during the loading process, and provided an energy dissipation mechanism, which could improve the mechanical properties of the laminated composite sheets obviously. When the theoretical amount of Ti2AlC was 20 wt %, the flexural strength and fracture toughness of the laminated composite sheets reached the maximum value in the arrester direction, which were 1428.79 MPa and 64.08 MPa·m1/2, respectively.
Fracture mechanism of a high tensile strength and fracture toughness Ti6Al4V–TiAl laminated composite
Abstract Ti6Al4V (wt.%)-Ti43Al9V0·3Y (at.%) laminated composites were fabricated from as-forged TiAl and commercial Ti6Al4V sheet by hot-pack rolling, and the microstructure of composites were investigated. The results showed that the target laminated composites were achieved by reaction and diffusion bonding. A defect free interfacial region was observed indicating that The Kirkendall effect was successfully avoided by substituting Al metal foils with Ti43Al9V alloy sheets. The microstructure, from the Ti6Al4V side to the Ti43Al9V side, had four different microstructure regions which are α+β, α2, α2+γ+B2 and B2+γ, respectively. The tensile properties and fracture toughness of composites were examined. It was noteworthy that the composites not only retained high tensile properties in both room temperature and 700 °C, but also possessed high fracture toughness. It was also proved that the unique mix-phase interfacial region obtained by hot-pack rolling has a great contribution to the improvement of the properties of composites and strengthening-toughening mechanism were clarified profoundly.
A study on tensile properties of a novel fiber/metal laminates
Abstract Fiber metal laminates (FMLs) are layered materials based on stacked arrangements of aluminum alloy layers and fiber reinforced plastic (FRP) layers. FMLs have benefits over both aluminum and fiber reinforced composites. In this work, glass fibers and Kevlar fibers are used together and effect of fibers orientation on tensile behavior of this novel material is investigated. A modified classical laminate theory (CLT), which considers the elastic–plastic behavior of the aluminum sheets, and a numerical simulation method based on finite element modeling (FEM) are used to predict the stress–strain response of FMLs. Specimens were made and mechanical testing was performed to determine in-plane tensile properties of this type of FMLs. Good agreement is obtained between the models predictions and experimental results. Test results show that fiber sheets with zero orientation in laminate improve modulus of elasticity, yield stress and ultimate tensile stress considerably. Statistical analysis of data is done and an estimated response surface of ultimate tensile strength of the specimens as a function of fiber orientation in each layer is obtained. Also, the effect of the independent variables and interactions with their relative significance on the tensile behavior is specified. It is shown that Kevlar fiber orientation is the most important parameter between all variables and their interactions.