ABSTRACT
The nanohardness, elastic modulus, anti-wear, and deformability characteristics of TiAl(100-x)-xTaN composites containing 0, 2, 4, 6, 8, and 10 wt.% of TaN were investigated via nanoindentation technique in the present study. The TiAl(100-x)-xTaN composites were successfully fabricated via the spark plasma sintering technique (SPS). The microstructure and phase formation of the TiAl sample constitute a duplex structure of γ and lamellar colonies, and TiAl2, α-Ti, and TiAl phases, respectively. The addition of TaN results in a complex phase formation and pseudo duplex structure. The depth-sensing indentation evaluation of properties was carried out at an ambient temperature through a Berkovich indenter at a prescribed load of 100 mN and a holding time of 10 s. The nanoindentation result showed that the nanohardness and elastic modulus characteristics increased as the TaN addition increased but exhibited a slight drop when the reinforcement was beyond 8 wt.%. At increasing TaN addition, the yield strain (HEr), yield pressure (H3Er2), and elastic recovery index (WeWt) increased, while the plasticity index (WpWt) and the ratio of plastic and elastic work (RPE) reduced. The best mechanical properties were attained at the 8 wt.%TaN addition.
ABSTRACT
The synthesis of x-wt.% (where x = 2.5, 5, 7.5, and 10) TiB2-reinforced titanium matrix was accomplished through the spark plasma sintering technique (SPS). The sintered bulk samples were characterized, and their mechanical properties were evaluated. Near full density was attained, with the sintered sample having the least relative density of 97.5%. This indicates that the SPS process aids good sinterability. The Vickers hardness of the consolidated samples improved from 188.1 HV1 to 304.8 HV1, attributed to the high hardness of the TiB2. The tensile strength and elongation of the sintered samples decreased with increasing TiB2 content. The nano hardness and reduced elastic modulus of the consolidated samples were upgraded due to the addition of TiB2, with the Ti-7.5 wt.% TiB2 sample showing the maximum values of 9841 MPa and 188 GPa, respectively. The microstructures display the dispersion of whiskers and in-situ particles, and the X-ray diffraction analysis (XRD) showed new phases. Furthermore, the presence of TiB2 particles in the composites enhanced better wear resistance than the unreinforced Ti sample. Due to dimples and large cracks, ductile and brittle fracture behavior was noticed in the sintered composites.
ABSTRACT
Nanostructured materials (NsM) are typical materials with structural length scales of one, two, or three dimensions in the range of 1-100 nm. In the development of NsM, the microstructure of a material, which is an integral factor in determining the intrinsic performance of a material, is susceptible to changes that may hinder the desired nano-state properties under different processing routes and associated varying processing parameters. NsM exhibits distinct superior properties when compared to conventional coarse-structured materials. They exhibit distinct and rapid development during production due to their unique surface area, which requires concise control measures over coarse materials. These promising excellent properties of nanocrystalline materials have caught the attention of material scientists and engineers towards their developments. In order to exploit the abundance of excellent properties of NsM, investigations on the processing-structure-property correlations have been employed in recent years to understand their complications and subsequent development of novel materials. This review aims to understand the sintering of nanomaterials, with a clear focus on the spark plasma sintering technique and its associated sintering parameters, bordering on intricate issues on densification, coarsening of particles, and grain growth.
ABSTRACT
The major objective of this work is to study the hardness data at the domain of ferrite and Austenite phases. Nanoindentation and microhardness study has been conducted on austenite and ferrite present in the microstructure of hot rolled and heat treated duplex stainless steel (2205 DSS). Furthermore, Optical microscopy and field emission scanning electron microscope (FE-SEM) were used to identify the microstructural distribution and phases present. Austenite reveals higher nanohardness data value than ferrite, as oppose to ferrite average elastic modulus which is higher than that of austenite. Also, higher value of microhardness data was observed for austenite in comparison with the ferrite at different load application.
