On the estimation of ultimate tensile stress from small punch testing

The Zn-0.5Cu alloy was investigated in as-cast, homogenized state and after carrying out equal channel angular pressing four times at room temperature via route BC. Microstructure analysis using light microscopy and SEM/EBSD was performed, as well as tensile tests, misorientation angle distribution and texture analysis. The initial microstructure with the average grain size of 560 µm was refined to a grain size of approx. 1 µm. The obtained microstructure consists of uniaxial grains separated mostly by high angle grain boundaries. Mechanical characterization was performed at strain rates from 2 × 10−6 s−1 to 1 s−1 at room temperature. Ultrafine-grained zinc-copper alloy exhibited 510% elongation with the strain rate sensitivity equal 0.31, which was the first observation of room temperature superplasticity in Zn-Cu alloys. Based on the microstructure, misorientation angle and texture analysis, the main operating deformation mechanisms were distinguished for samples deformed at strain rates from 2 × 10−5 s−1 to 10−1 s−1.

Achieving room temperature superplasticity in the Zn-0.5Cu alloy processed via equal channel angular pressing

Data-driven evaluation of fatigue performance of additive manufactured parts using miniature specimens

Experiments were carried out to determine the minimum material volume in the gauge section of miniature tensile test specimens required to get mechanical properties data comparable to those from standard test specimens. The experimental results were verified and aided by numerical and metallurgical analysis simultaneously. In order to generalize the results, three different materials, having large variation in their mechanical properties, were selected for the study.

Optimisation of thickness of miniature tensile specimens for evaluation of mechanical properties

In this study, the graphene reinforced aluminium matrix nanocomposite is fabricated through the combination of high energy ball milling (HEBM) and molecular level mixing (MLM) processes followed by spark plasma sintering (SPS) method. FTIR, XRD and FESEM analyses revealed that Cu/RGO nanocomposite was well synthesized by the MLM method with a uniform distribution of Cu nanoparticles on RGO surface. XRD and Raman spectroscopy showed that no Al4C3 phase was formed during the manufacturing process, but Al2Cu fine particles precipitated during the SPS treatment which were smaller in size and more uniform in distribution when RGO was used as reinforcement according to TEM analysis. Grain refinement of the nanocomposites was also investigated in the presence of RGO by EBSD method. The results showed that with increasing RGO content from 0 to 1 wt %, the coarse grained microstructure changed to bimodal microstructure. In addition, the mean grain size decreased from 3.9 to 1.6 μm, and dislocation density increased significantly with the increased RGO content. The SPS process also resulted in a nearly fully dense nanocomposite with a relative density higher than 99%. The investigation of mechanical properties of the sintered nanocomposite indicated an improvement of 79, 49 and 44% of yield strength, ultimate strength, and Vickers hardness, respectively, for only 1 wt % graphene containing nanocomposite in comparison to the unreinforced Al–4Cu alloy.

Application of a novel method for fabrication of graphene reinforced aluminum matrix nanocomposites: Synthesis, microstructure, and mechanical properties

Arun Pooleery

Papers

Use of Miniature Tensile Specimen for Measurement of Mechanical Properties

Optimisation of thickness of miniature tensile specimens for evaluation of mechanical properties

Evaluation of ultimate tensile strength using Miniature Disk Bend Test