In recent years, research on ultra-fine grain materials has gained attention. While attempts have been made to improve the properties of the material, it has also become increasingly important to decrease the costs. Studies on improving material properties have revealed new production methods or have required the revision of existing production methods. In this direction, severe plastic deformation methods have come to the fore as a good alternative, and by improving the methods with new variations, materials with grain sizes below 1 µm have been obtained. In addition, this method positively affects the mechanical properties of the material. In this study, the Equal Channel Angular Pressing (ECAP) method, one of the severe plastic deformation methods, which has attracted great attention among researchers, was examined and the development stages of the method were investigated according to recent studies. The effective parameters in the method were examined and the effects of these parameters on the grain structure and mechanical properties of the material were discussed. Channel shapes, which are open to innovation and increase the efficiency of the ECAP method, were kept in the foreground among the prominent parameters in the ECAP process, and the results of the design changes made with new variations were examined.

Parts produced using a 3D printer are combined with friction stir welding (FSW). In the FSW processing of parts with a low infill ratio, welding errors occur due to a lack of material. In this study, plates were created using two different-colored PLA Plus filaments with different infill ratios in the weld area (20%, 60%, and 100%). Triangular pin geometry, different feed rates (20, 40, and 60 mm/min), and different tool rotation speeds (1250, 1750, and 2250 rpm) were used as FSW process parameters. Tensile testing was performed to determine weld strength and hardness measurements, and visual inspections were performed. Color measurements were made on the test samples before and after the welding process, and the relationship between welding performance and color was evaluated. The best welding strength was obtained as 17.83 ± 0.68 MPa at a feed rate of 20 mm/min, a tool rotation speed of 1750 rpm, and a part with a 60% infill ratio in the welding zone. In the sample with the best weld strength, the temperature was measured as 198.97 °C. Color changes in the weld area of parts with 60% and 100% infill ratios were measured between 78.9–82.2 and 79.1–84.5, respectively. It was determined that the color change decreases as the weld strength increases in these parts. The results show that with the proposed new part design, the FSW method can be used at low infill ratios, and the weld strength can be evaluated based on the color changes in the weld zone.

Since their inception, plastics have become indispensable materials. However, plastics used for extended periods in industrial applications are prone to aging, which negatively impacts their material behavior and performance. To ensure the long-term usability of these materials, they must be tested in real-time, in-service environments to assess degradation. In practice, however, accelerated aging techniques are commonly employed to avoid time loss. Over time, various indicators of degradation in plastics emerge, such as changes in molecular weight, cracking, and mechanical properties like strain at break and impact strength. Among these, color deterioration or change is a critical factor that helps evaluate the service life of these materials. Considering the increasing use of plastics in 3D printing today, and the growing focus on strength over aesthetics in these applications, it is particularly useful to evaluate aging in plastics based on the relationship between color and strength. The wide application of 3D printing in various industries necessitates understanding material properties under aging conditions. This study examines the effects of aging on the mechanical behavior of polylactic acid (PLA) with three different colors (yellow, orange, and red) and three different infill ratios (20%, 60%, and 100%). The samples underwent an accelerated aging process of 432 h, which included 8 h of UV radiation, 15 min of water spraying, followed by 3 h and 45 min with the UV lamps turned off. Tensile tests, bending tests, hardness measurements, and color evaluations were conducted on the samples, linking the color changes after aging with the materials’ mechanical properties. The results show that after aging, yellow samples with a 100% infill ratio exhibited a 6.9% increase in tensile strength (44.50 MPa to 47.58 MPa). Orange samples with a 100% infill ratio were less affected by aging, while red samples experienced a decrease in tensile strength across all infill ratios. Regarding bending force, increases were observed in the orange, yellow, and red samples by 10.37%, 25.05%, and 8.87%, respectively. This study underscores the importance of color selection when designing 3D-printed materials for long-term applications.

The use of plastic materials in the maritime industry is increasing day by day. Plastics are particularly preferred in watercraft due to their lightweight, resistance to water-related damage (such as mold and wear), optical clarity, and high corrosion resistance. In recent years, plastics produced by 3D printing have gained prominence in applications traditionally dominated by conventional plastic materials. Therefore, producing marine-grade materials—such as acrylonitrile butadiene styrene (ABS), which has long been used in the maritime sector—through 3D printing, and understanding their long-term performance, has become increasingly important. In this study, the mechanical behavior, surface roughness, and color changes of ABS+ materials in three different colors (yellow, green, and blue) and with three different infill ratios (50%, 75%, and 100%) were investigated after a salt spray test. Following the salt spray exposure, tensile and bending tests, hardness measurements, surface roughness analyses, and color measurements were conducted and compared with reference samples. The results were evaluated based on filament color and infill ratio. This study underscores the importance of color selection—along with mechanical strength—when designing 3D-printed materials for long-term use in saltwater environments.

Aşırı plastik deformasyona maruz bırakılma işlemi, malzemenin mekanik özelliklerini geliştirmek amacıyla ultra ince tanelerin oluşturulmasına olanak sağlamaktadır. Aşırı plastik deformasyon yöntemlerinden biri olan Eşit Kanallı Açısal Presleme (EKAP) yöntemi de malzeme kesitinde herhangi bir değişiklik olmadan, malzemenin kayma gerilmelerine maruz kalması sonucu mekanik özelliklerin iyileşmesine imkân sağlayan bir yöntemdir. Bu yöntemle malzemelerin mekanik özelliklerin daha da artması hem işlem parametrelerine ve hem de işlem parametrelerinin optimizasyonuna bağlıdır. Özellikle, malzemenin kanal içerisinden geçişi sırasında kalıp açıları kritik öneme sahiptir. Bu açılar, uygulanacak olan kuvvet ve deformasyon miktarı üzerinde doğrudan etkilidir. Deneysel süreç başlamadan malzemede meydana gelebilecek deformasyonu önceden tahmin etmek sürecin doğru ilerlemesi açısından çok önemlidir. Bu çalışmada tane boyutu üzerinde en etkili parametrelerden olan kanal açısı, dış kavis açısı ve iç köşe kavis değeri dikkate alınmıştır. Kanal açısı (Φ) 90o ve 120o, dış kavis açısı (ψ) 0o ve 20o, iç köşe kavis değerleri ise 0, 2, 4, 6, 8, 10 mm olarak alınmıştır. Kalıp ile numune arasındaki temas şekli, sürtünmesiz olarak kabul edilerek numunenin uğradığı deformasyon miktarı tespit edilmiş ve gerekli olan kuvvet değeri hesaplanmıştır. Elde edilen verilere göre en yüksek gerilme değeri Φ=90o, ψ=20o ve r=0 mm olan modelde gözlenmiştir. Kanal açısının artırılması kuvvet değerini azaltırken deformasyon miktarını da düşürmektedir. İç köşe kavis değerinin artması Φ=90o kanal açısı için gerilme değerlerinde önemli değişiklikler göstermesine rağmen Φ=120o kanal açısı için kayda değer değişiklikler gözlenmemiştir.

As the global 3D printing market continues to grow, the consumption of plastic products produced by 3D printers is also increasing. The role of 3D-printed products in both daily use and industrial applications has been progressively reinforced. Plastic materials undergo physical and chemical changes when exposed to environmental conditions such as temperature, light, and humidity. Consequently, they are subjected to aging during use, which shortens their service life. With the expanding use of 3D printing technology in various sectors such as healthcare, automotive, aerospace, and defense, it has become increasingly important to understand the changes (potential decreases or losses) in the performance of these materials after long-term exposure to environmental conditions. This study aims to contribute to the understanding of potential changes in 3D-printed ABS Plus material by examining the phenomenon of aging induced by exposure to radiation from a xenon arc lamp. ABS Plus samples of different colors (yellow, purple, red, green, and blue) were subjected to aging for 0, 112, 225, 337, and 450 h using a xenon arc lamp. To investigate the effects of aging, the mechanical (tensile, flexural, and hardness) and optical (color and gloss variations) properties of the samples were compared before and after aging. Following the mechanical tests, the fracture modes of the specimens were also examined. In addition, Scanning Electron Microscope (SEM) images were obtained to further discuss the effects of aging. The results revealed that the mechanical properties of the reference samples varied depending on color. The highest tensile strength was observed in the yellow samples (33.46 MPa), while the highest flexural strength was recorded in the green samples (58.46 MPa). After aging, the lowest tensile strength was found in the purple samples aged for 337 h (24.63 MPa), whereas the lowest bending force was measured in the red samples aged for 450 h (45.27 N). Overall, the mechanical properties of the samples varied with aging duration, with the blue and green specimens being the least affected. For the blue specimens, after 112, 225, and 337 h of aging, an increase in tensile strength was observed (2.77%, 10.54%, and 9.58%, respectively), while a decrease occurred after 450 h of aging (−6.22%). For the green specimens, after 112, 225, and 337 h of aging, the tensile strength remained similar to that of the reference sample (−2.97%, 0.23%, and 0.05%, respectively) but decreased after 445 h of aging (−8.09%). In terms of optical properties, the most significant color change (−23.51) was observed in the purple samples. Gloss measurements indicated that the impact of aging increased with exposure time.