International Journal of Lightweight Materials and Manufacture最新文献

This paper proposes an innovative multi-scale method for determining gas pressure parameters of superplastic forming, which is based on the quantitative relationship between the grain growth mechanism and fracture mechanism of Ti–6Al–4V alloy. The high-temperature tensile tests were conducted on the material at temperatures ranging from 700, 800, 840, 890, 920, and 950 °C, strain rates were selected as 10⁻²∼10⁻⁴/s. The grain size measurements were observed using electron back-scatter diffraction (EBSD). Particularly, the relation between grain size changes and fracture behaviour is specifically discovered using a physically-based dynamic material model (DMM), and the grain size thresholds for each forming limit are proposed. The physical fracture mechanism is named the “Grain growth based fracture (GGBF)” mechanism. Furthermore, an innovative method based on the GGBF mechanism is proposed to design the superplastic forming loading, and practical four-layer hollow structures experiments are applied to validate the fracture mechanism in superplastic forming. In total, A superplastic forming GGBF mechanism has been verified, and it is expected to be helpful for shape and property control in the forming process of complex structures.

Current advancements in technology enables the enhancement and refinement of alloys to address the demands of expanding industrial applications. High Entropy Alloys (HEAs) are a developing class of alloys displaying unique and advanced mechanical, tribological, thermal stability, and corrosion properties. HEAs have unpredictable structures and compositions displaying enhanced performance and characteristics. Unique microstructures can be achieved through multi-principal elements and HEAs usually outperform conventionally made alloys. Lightweight HEAs (LWHEAs) are a category of HEAs with alloy density less than 6 g/cm³ and are potentially applicable in the automobile and aerospace industries. The superior characteristics make LWHEAs an extremely interesting space for research. Recent research has focused on effective manufacturing methods for processing alloys, coatings, and surface modifications. The current work discusses a comprehensive review of fabrication processes, mechanical, tribological, and corrosion behavior of LWHEAs. The review also highlights the future scope of research and directions for designing LWHEAs. The results of the article provide crucial information to researchers and pioneers exploring LWHEAs.

Leak proof tube-to-tube sheet joints are mandatory for the optimal operation and longevity of the shell and tube heat exchanger. Tube-to-tube sheet joints play a crucial role as fluid barriers, ensuring effective separation between the tube and shell side fluids within shell and tube heat exchangers. Non-conventional friction stir welding, known for imparting less residual stresses, is not commercially used for the fabrication of tube-to-tube sheet joints due to complex joint configuration and geometrical limitations. An extensive study on friction stir welding considering the geometrical parameters of tube-to-tube sheet arrangement is highly demanded. This research examined the mutual influence of radial clearance ranging from 0 mm to 0.5 mm and tube projection lying from 1 mm to 2 mm in friction stir welding of tube to tube sheet configuration on the pull-out strength, extension and, hardness at the stirring and fusion zones. Optimum radial clearance and tube projection for achieving high mechanical weld properties was estimated using multi-objective integrated Taguchi-PCA-GRA optimization. The result proves that the friction stir welded joint is capable of achieving joint strength close to the tungsten inert gas welded joint. The optimum parameters are 2 mm for tube projection and 0 mm for radial clearance to achieve maximum strength and weld penetration, while minimizing hardness at both stir zone and fusion zone. The findings of this research proved the adaptability of friction stir welding for the fabrication of tube-to-tube sheet joints with the right choice of tube projection and radial clearance.

Wire arc additive manufacturing (WAAM) has increasingly been recognized as a cost-effective method for fabricating intricate metallic parts, especially from nickel-based superalloys. This review covers key aspects of WAAM, including its versatile heat sources (GTAW, GMAW, CMT, and PAW) with unique advantages and limitations for customization. Design for Additive Manufacturing (DfAM) principles are highlighted, enabling intricate geometries and addressing support structures, distortion control, and orientation.

Several nickel-based superalloys (e.g., Inconel 718, Inconel 625, Inconel 617, Hastelloy C276, Hastelloy X, Haynes 282) are rigorously evaluated for WAAM suitability due to their high-temperatureature strength, corrosion resistance, and mechanical properties. The review analyzes process parameters like arc current, wire feed rate, and deposition path. It explores defect detection and prevention strategies and emphasizes post-processing methods (heat treatment, rolling, hot isostatic pressing) in enhancing microstructural characteristics and mechanical properties.

Microstructural characterization techniques (optical microscopy and XRD) provide insights into grain structure, phase composition, and defect presence. In conclusion, this review underscores the paramount suitability of WAAM for producing defect-free and complex structures in nickel-based superalloys. Ongoing research and advancements in WAAM will undoubtedly improve its competitiveness and unlock its full potential in the field of additive manufacturing.

Expanding the use of 6xx aluminum alloy series in various industries is challenging due to the need for cost-effective welding processes and optimal settings to ensure high-quality joints. The present research focused on the comparison of joint performance of the pipes and plates using tungsten inert gas (TIG) and friction stir welding (FSW) The AA6082 alloy material is used for pipes and plates used in the study. Various techniques were utilized, including hardness and tensile tests, and microstructural examinations. Using a scanning electron microscope (SEM), the surface fracture of the specimens that failed under tensile tension was also examined. The present research also included the economic impact on the welding processes used. Results demonstrated that the weld obtained using FSW was defects free whereas, internal flaws were seen in TIG welded samples. The hardness value increased over the base material (BM) for the FSW and TIG by 31–35% and 46-40%, respectively. The FSW joint was welded at a maximum UTS of 3 mm/min and a rotational speed of 3000 rpm. FSW can create the AA60682 flange joints more efficiently and effectively than fusion welding procedures like TIG processes in pipeline applications. For AA6082 flange joints, overall total cost comparisons between FSW and TIG were also made.

The main task of this work is the optimization of the manufacturing process of Al-alloy lattice cellular structures with rhombic cell, obtained with lost-PLA technique. It is an easy, environment sustainable and economical technique (both for infrastructure and operating costs) for the manufacturing of Al porous structure based on the 3D printing of PLA and replication process alternative to that based on expensive metal 3D printers. Plaster processing, PLA burnout and AA 6082 alloy casting conditions and parameters have been suitably tuned in order to get final samples with geometry and surface finishing conditions identical to the starting ones made in PLA. A good replication process has been implemented with a high repeatability rate and accurate surface finishing, comparable with that of the PLA printed objects. Morphological analysis on PLA and Al 6082 was conducted as well microstructural analysis and Vickers microhardness tests on Al alloy samples in the as-cast conditions. Metallography reveals the presence of AlFeSi and AlFeMnSi intermetallic phases at the cell boundaries and some coarse precipitates Mg₂Si in the AA 6082 alloy. Microstructures and HV measured values are aligned with literature data for this alloy in the same (as-cast) conditions.

The fabrication of dissimilar metal joints, particularly between AA 6061 aluminum alloy (Al) and AZ31B magnesium alloy (Mg), poses significant technical challenges due to their distinct metallurgical characteristics and the inherent difficulties associated with welding such materials. These challenges include the propensity for intermetallic compound formation, thermal cracking, and differences in thermal and mechanical properties between the two alloys. Cold Metal Transfer (CMT) welding, known for its low heat input and controlled metal transfer, offers a potential solution to these issues. However, optimizing the process parameters to ensure strong, defect-free joints requires a systematic approach. This study aims to optimize CMT welding parameters using parametric mathematical modeling (PMM) to produce high-strength Al and Mg dissimilar joints and to study the effects of CMT parameters on tensile strength (TS) and weld metal hardness (WMH), as well as the microstructural features of AA 6061 aluminum alloy/AZ31B magnesium alloy (Al/Mg) dissimilar joints. Al/Mg dissimilar butt joints were produced by the CMT process using ER4043 as filler wire. CMT, a low-heat input welding technique, was used to mitigate issues such as intermetallic compounds (IMCs), wider heat-affected zone (HAZ), and distortion. The CMT parameters, particularly wire feed speed (WFS), welding speed (WS), and arc length correction (ALC), were optimized using response surface methodology (RSM) to maximize the TS and WMH of the Al/Mg dissimilar joints. Polynomial regression was employed to create PMMs that integrated these CMT parameters to forecast the TS and WMH of the joints. An analysis of variance (ANOVA) was applied to assess the feasibility of the PMMs. The results indicated that the Al/Mg dissimilar joints, produced using a WFS of 4700 mm/min, a WS of 280 mm/min, and an ALC of 10%, exhibited higher TS and WMH values of 33 MPa and 95.8 HV, respectively. The PMMs provided precise forecasts for the TS and WMH of the Al/Mg joints with an error rate of less than 1% and a confidence level of 97%.

This research dealt with fabrication of suitable lightweight composite panel samples from sawdust for building applications. Raw and alkali-treated sawdust particles were utilized at varying weight proportions (0 %, 25 %, 50 %, 75 %, and 100 %) to develop the samples with topbond as binder. From the results of heat transfer and strength properties tests, the raw sawdust improved thermal insulation efficiency while the treated sawdust enhanced the strength of the samples. For each loading level of sawdust, 100 % screwability and nailability were achieved. The findings suggest that, if used as ceiling panels in buildings, the samples would outperform conventional ceilings like plywood, asbestos, plaster of Paris, and KalsiCeil in mitigating global warming effects, reducing dead loads, and promoting sustainable and cost-effective housing development. This underscores the potential of these samples to address key priorities in construction and environmental sustainability.