Search results

Computer tomography (CT) is widely used in engineering applications, allowing for precise structural analysis of materials and components, enabling the measurement of internal properties and features, which is crucial for assessing their quality and durability. Therefore, the purpose of this study is to analyze the fatigue fracture surface features of titanium alloy (Ti-6Al-4V) under different loading configurations and structure orientations using computational micro-tomography.

In this work, the specimens were fabricated by selective laser melting (SLM) and subjected to fatigue tests to analyze the effects of different printing parameters on mechanical properties and microstructural features. The comprehensive methodology included metallographic testing, fatigue life testing, fractographic analysis and CT analysis, followed by microhardness measurements, providing a detailed assessment of internal defects and their impact on fatigue performance.

The fatigue test results showed better fatigue life for samples printed with Y orientation followed by X and Z orientation. The measurement values were fitted to obtain mean variable values of A as 6.522, 10.831 and 6.747 and values of m as −0.587, −2.318 and −0.771 for samples printed with X, Y and Z orientation for the Basquin’s equation to determine fatigue life. CT analysis revealed that the mean equivalent defect diameters were 0.0506, 0.0496 and 0.0513 mm and mean defect volume of 0.000714, 0.000467 and 0.000534 mm³ for X, Y and Z orientation samples, respectively.

The novel aspect of this study is to investigate the effect of extreme SLM process parameters on the durability of the material subjected to complex multiaxial loading conditions, including nonproportional fatigue loading.

Additive manufacturing (AM), a rapidly evolving paradigm, has shown significant advantages over traditional subtractive processing routines by allowing for the custom creation of structural components with enhanced performance. Numerous studies have shown that the technical qualities of AM components are profoundly affected by the discovery of novel metastable substructures in diverse alloys. Therefore, the purpose of this study is to determine the effect of cell structure parameters on its mechanical response.

Initially, a methodology was suggested for testing porous materials, focusing on static tensile testing. For a qualitative evaluation of the cellular structures produced, computed tomography (CT) was used. Then, the CT scanner was used to analyze a sample and determine its actual relative density, as well as perform a detailed geometric analysis.

The experimental research demonstrates that the mechanical properties of a cell’s structure are significantly influenced by its shape during formation. It was also determined that using selective laser melting to produce cell structures with a minimum single-cell size of approximately 2 mm would be the most appropriate method.

Further studies of cellular structures for testing their static tensile strength are planned for the future. The study will be carried out for a larger number of samples, taking into account a wider range of cellular structure parameters. An important step will also be the verification of the results of the static tensile test using numerical analysis for the model obtained by CT scanning.

The fabrication of metallic parts with different cellular structures is very important with a selective laser melted machine. However, the determination of cell size and structure with mechanical properties is quiet novel in this current investigation.