Materials Testing

doi: 10.1515/mt-2024-frontmatter11pmid: N/A

Savaş, Cihan; Altın, Murat; Güler, Mehmet Ali; Acar, Erdem

doi: 10.1515/mt-2024-0253pmid: N/A

AbstractBio-inspired structures have applications in various industries, including automotive, defense, aerospace, and biomedical industries, owing to their combination of high-strength and lightweight properties. To enhance their energy absorption performance, a novel design was developed by integrating a spiral component, inspired by the cross section of the date palm tree trunk (Latin: Phoenix dactylifera), into an empty aluminum tube. The energy absorption performance of a bio-inspired hybrid energy-absorbing profile (BIHEAP) was experimentally and numerically investigated. To ensure the reliability of the numerical studies, finite element models were generated using ANSYS LS-DYNA and subsequently validated through axial crushing tests. Design optimization studies were carried out using surrogate-based models, such as the response surface model and Kriging surrogate models, to increase the energy absorption performance of the BIHEAP, which has three different design variables (spiral revolution, wall thickness, and number of spiral tubes). The initial design of the BIHEAP exhibited a specific energy absorption capacity (SEA) and crush force efficiency (CFE) that surpassed those of the empty aluminum tube by 17.2 % and 4.6 %, respectively. The optimized BIHEAP design demonstrated SEA and CFE values that were 21.4 % and 32 % greater than those of the empty aluminum tube, respectively. When the initial and optimized BIHEAP design were compared, it was found that SEA and CFE was increased by 3.5 % and 26.1 %, respectively.

Dvorak, Karel

doi: 10.1515/mt-2024-0261pmid: N/A

AbstractASTM F543 specifies the testing characteristics of bone screws. It consists of 4 phases of separate tests, 3 of which are carried out according to a standard procedure using strictly prescribed material. Testing according to this standard is part of the standardization and certification process for bone implants. The PUR 30 PCF material simulates bone for the respective test. The standardized testing results are primarily used to compare the characteristics of the implants tested. At the same time, the information obtained is essential for the verification of real bone screw implantation procedures. In addition to the design of implants and fixation elements, the purpose of using the results of testing using a surrogate material may be, for example, to teach implantation procedures or to train and simulate real implantation procedures, especially in complicated cases. The advantage of using bodies made of poly lactic acid (PLA) material, prepared by additive technology, lies mainly in the possibility of realizing free shapes corresponding to the shapes of natural bone. The present content introduces the problem of defining the structure of test bodies made of additively prepared PLA material and presents the results of comparative testing with PUR 30 PCF material.

Xue, Chuanmei; Dai, Liangwei; Dai, Jiren; Wang, Zhaoyu; Tian, Wenchun; Xue, Kemin

doi: 10.1515/mt-2024-0027pmid: N/A

AbstractTo refine the grains of reduced activation ferritic/martensitic steel, the closed dual equal channel angular pressing deformation is used. The effects of the deformation on the microstructure, precipitation phase, and mechanical properties of reduced activation ferritic/martensitic steel are studied. The results show that the closed dual equal channel angular pressing deformation can refine the grains of reduced activation ferritic/martensitic steel. The grain size of the deformed reduced activation ferritic/martensitic steel decreases gradually with increasing deformation pass. After four deformation passes, the grain sizes in the elongation deformation zone and shear deformation zone are refined to 0.68 μm and 0.71 μm, respectively. With increasing deformation pass, the hardness and yield strength increase. After four deformation passes, the yield strengths in the elongation deformation zone and shear deformation zone increase to 1,093.3 MPa and 1,021.1 MPa, respectively.

Yilmaz, Ummihan T.; Erkan, Ayse; Akar, Neset; Kilicli, Volkan

doi: 10.1515/mt-2024-0062pmid: N/A

AbstractThis study investigates the influence of post-oxidation duration on the wear performance and microstructural features of AISI 4140 steel subjected to nitrocarburizing followed by post-oxidation. For this aim, the quenched and tempered AISI 4140 samples were nitrocarburized (NC) and post-oxidized (PO) at various times (45–180 min) under low vacuum. Microstructural features were investigated using optical microscopy, scanning electron microscope (SEM), energy-dispersive X-ray spectrum analysis (EDS), X-ray diffraction (XRD) analysis, and microhardness test. Wear behavior was evaluated using a ball-on-disk tribometer. Experimental results showed that the structures consisting of nitride layer (ε-Fe2–3N) and γ′-Fe4N + iron oxide (Fe3O4) were obtained at the top surfaces of the samples. Increasing post-oxidation times resulted in a notable enhancement in the thickness of the Fe3O4 layer. The growing Fe3O4 layer has induced the closing of micro porosities for further post-oxidizing times, leading to decreased surface roughness of the samples. It was determined that the post-oxidation times have no significant effect on the hardness profiles of NC + PO samples. The highest (0.375) and lowest (0.276) mean coefficient of friction was obtained in the post-oxidation times of 150 and 180 min, respectively. The best wear rate was obtained in the post-oxidized sample for 150 min.

Yilmaz, Serdar Osman; Teker, Tanju; Milli, Ahmet

doi: 10.1515/mt-2024-0155pmid: N/A

AbstractIn this study, the microstructure and mechanical performance of Fe-based composites reinforced by FeTi+B4C at various ratios were determined. The study was based on the production of Fe based nano carbide and boride (B4C, Fe2B, Fe7C3, TiB2) reinforced composites. Mechanical alloying technique was chosen to reduce the reinforcement material to nano size and distribute it homogeneously. Sintering temperature was used as 1,100 °C and sintering time as 2 h. The reionforcement “FeTi+B4C” ratio was raised up to 15 wt.%. The microstructure and phases of the composite samples were descrived by scanning electron microscopy, energy dispersive spectroscopy, X-RD analysis and hardness. The concentration of voids and the stiffness changes of the samples were determined. The size of TiC and TiB2 particles reduced significantly with the rise in B4C ratio. Since the hardness of TiB2 was less than that of the B4C matrix, the hardness reduced with increasing TiB2 ratio.

Maurya, Manish; Maurya, Ambrish; Kumar, Sudhir

doi: 10.1515/mt-2024-0073pmid: N/A

AbstractWith the fast progress of industrial manufacturing, friction stir additive manufacturing has fascinated wide-ranging consideration in the industry due to high material consumption rate. Friction stir additive manufacturing (FSAM), a newly developed solid-phase additive manufacturing technique was employed to fabricate AA6061/TiC/GS composite. The process parameters like tool rotational speed, transverse speed, tool tilt angle and type of tools used in friction stir additive manufacturing were analyzed. Taguchi’s L16 orthogonal array and ANOVA method was used to find the optimum process parameters for the tensile strength. Development characteristics of stirred zone, recrystallization and mixing of reinforced particles will significantly improve the mechanical properties of the fabricated composites. Microstructural investigation and fractography was done by using optical microscopy and scanning electron microscopy (SEM). Corrosion, wear behavior and elemental analysis through EDS was also performed for the fabricated material. The maximum tensile strength of 385.74 MPa was attained under optimal parameters of the tool rotational speed 1,200 rpm, transverse speed 55 mm min−1, and tool tilt angle of 1° for scrolled tapered octagonal tool pin. The findings of the linear regression model showed a minor variance between model and experimental values. Prominent results of the experiment were compared by few other researcher’s findings working in similar area.

Tütük, İbrahim; Acar, Serhat; Özer, Gökhan; Güler, Kerem Altuğ

doi: 10.1515/mt-2024-0078pmid: N/A

AbstractWith its computer-aided layer-by-layer production approach, additive manufacturing (AM) and powder bed laser fusion (PBLF) paved the way to produce metallic parts more precisely than any other manufacturing technique. However, the combinability and the interaction of this relatively new manufacturing technique with the other near-net shape production techniques is still a mystery. In this study, the recrystallization and partial melting (RAP) behavior, which is a feedstock production approach for semisolid forming methods, investigated on AlSi10Mg parts produced by PBLF and conventional casting were compared in terms of microstructural and hardness evaluations. After the reheating process, the globalization of Si particles and the breakdown of the Si network around the melt pools were displayed with light microscope and scanning electron microscope (SEM) images. The hardness values of the PBLF as-fabricated specimens were found to be significantly higher than the as-cast specimens; however, the values were almost equaled after the RAP treatment and even got lower on the bottom and top regions of the PBLF samples after 20 min of reheating because of the enlarged shrinkage porosities and the coarsened morphology.

Siddharthan, Balakrishnan; Kumaravel, Arumugam

doi: 10.1515/mt-2024-0143pmid: N/A

AbstractThis study investigates the wear behaviour of a hybrid composite material reinforced with titanium diboride and zirconium carbide in LM13. The ASTM standard is followed for conducting wear tests, utilizing a pin-on-disc setup to assess the wear rate. An empirical relationship is established to predict the wear rate using statistical tool analysis of variance, and the model’s adequacy is checked. Low wear is observed at a sliding distance of 110 mm, sliding speed of 2.5 m s−1, and sliding load of 12.5 N. The observed low wear is attributed to the optimal level of reinforcement provided by titanium diboride and zirconium carbide. From the analysis of variance, sliding speed is identified as the major contributing factor to wear rate, followed by sliding distance and load. The reinforcement materials enhance the wear resistance of the hybrid composite and their effectiveness is particularly evident under the specified sliding conditions.

Kaya, Esad; Ulutan, Mustafa; Çakır, Ersin; Buytoz, Soner

doi: 10.1515/mt-2024-0273pmid: N/A

AbstractMetallic alloys are increasingly being produced using wired arc additive manufacturing (WAAM). In this study, 18Ni300 defect-free maraging steels were produced using the WAAM technique. A traditional solution treatment, direct aging, and cryogenic heat treatment processes were applied to the WAAM produced maraging steels. The influence of conventional and novel cryogenic heat treatments on microstructural, mechanical, and tribological properties were examined. The microstructure of the as-built materials obtained by WAAM thermal cycling has mainly been homogenized through the solution, direct-aging, and cryogenic heat treatments. As a result, homogeneously distributed precipitate phases were obtained and the hardness increased by 30 % with a combination different post heat treatments. The cryogenic heat treatment improved the martensitic transformation and facilitated the formation of various Fe–Ni–Mo–Ti-containing intermetallic precipitates. Similarly, because of the different heat treatments, the wear resistance improved by a factor of 2–5.5 relative to the as-built material. Adding the cryogenic heat treatment to the traditional heat treatment procedure improves wear resistance by a factor of 1.2–2.9.