Materials & Design最新文献

Musculoskeletal disorders, as one of the prevalent categories of ailments, exert significant impacts on individuals’ lives, occupations, and physical activities. Degenerative changes, injuries, infections, and tumor resections causing defects in musculoskeletal tissues such as cartilage, bones, skeletal muscles, menisci, ligaments, and rotator cuffs can detrimentally affect patients’ quality of life and mental well-being. Traditional autologous and allogeneic transplantations have been clinically employed. However, autologous transplantation suffers from the limitation of a finite number of transplantable tissues, while allogeneic transplantation faces challenges such as immune rejection. The extracellular matrix (ECM) serves as a natural scaffold for cells to fulfill physiological functions such as adhesion, proliferation, and differentiation. Decellularized extracellular matrix (dECM) emerges as a promising biomaterial generated through specific tissue or organ decellularization. Leveraging 3D bioprinting technology, dECM-based biomaterials enable customized printing and construction. This study reviews various decellularization techniques, post-decellularization strategies, and commonly used 3D bioprinting technologies. It summarizes the integration of dECM-based biomaterials with 3D bioprinting technology applied in musculoskeletal system research. These investigations showcase the exciting potential of dECM-based biomaterials in the musculoskeletal system, offering prospects for clinical translation in orthopedics.

In industrial practice, no sensors capable of obtaining microstructural information in situ during thermo-mechanical processing of Al alloys are commonly employed. Inductive electrical conductivity measurement is safe, inexpensive, and capable of acquiring valuable information about precipitation and dissolution processes. However, commercial eddy current sensors work only at low temperatures near room temperature and are thus not suitable for in situ conductometry during heat treatments of Al alloys. We designed a high-temperature eddy current sensor and performed in situ conductometry during the homogenization of six Al-Mg-Si wrought alloys, three of which are experimental recycling-friendly alloys with increased Fe content. The results are interpreted with regard to microstructural investigations, and the advantages and limitations of our approach are discussed. As a proof-of-concept, we show how the conductivity curves and extrusion process parameters can be combined to predict final extrudate grain structures using machine learning. To achieve this, we employed finite element simulation of extrusion coupled with microstructural simulation over a wide parameter range, validated by extrusion experiments and metallography, and trained a feedforward neural network. We believe our interdisciplinary approach can lead to improvements in the industrial processing of Al wrought alloys.

Improvements in current design approaches require further studies of the damage interaction effects of composite materials subjected to repeated out-of-plane concentrated loads. To that end, a combined simulation and experimental investigation on composite laminate under repeated indentations is reported. The repeated indentations consist of seven identical peak-force indentations that are separately applied to the centre of the laminate. The results show that delaminations grow in all seven indentations, which can be interpreted as a continuous degradation of the effective delamination growth threshold with each subsequent indentation. More specifically, the second indentation effective delamination growth threshold is 62.4 MPa, which is about 19 % lower compared to the first one (77.2 MPa). Subsequently, the delamination growth threshold degraded approximately linearly with indentation. This effective delamination growth threshold reduction can be associated with the occurrence and evolution of the crack-rich zone preceding the delamination front.

A modified Miura foldcore geometry was developed by introducing sub-folds into the cell walls of a conventional Miura foldcore. Similar to other sub-fold Miura foldcores, stable plastic hinge lines were generated at sub-fold sites under the guidance of the sub-folds and transformed into traveling hinge lines or stationary hinge lines in the subsequent crushing process. Therefore, in comparison to the conventional foldcore, the dual-sub-fold Miura foldcore exhibited a higher average crushing force with an improvement of 60.8 % in the optimum case. The dual-sub-fold Miura foldcore exhibited relatively lower stiffness at the sub-fold sites, effectively reducing the initial peak crushing force. This reduction in peak crushing force reached a maximum decrease of 70 %. Moreover, this dual-sub-fold foldcore was glued to two parallel rigid plates (top and bottom), making it more suitable for engineering applications. The parametric study indicated that the dual-sub-fold Miura foldcore exhibited predictable and stable deformation modes. It was found that the average crushing force could be effectively enhanced by reducing the core folding angle, elevating the sub-fold position, decreasing the sub-fold size, and elongating the foldcore. The theoretical model for predicting the energy absorption performance of the foldcore was also established.

The corrosion performance of martensitic steel remains a matter of dispute, with no consensus on whether it exhibits heightened or diminished corrosion resistance. In this study, the corrosion behavior and mechanism of martensitic steel were systematically investigated by simulating a cargo oil tank environment. The results indicate that under strong acidic conditions, the corrosion rate of martensite (1.1404 mm/y) is significantly higher than that of ferrite-pearlite (0.7430 mm/y) due to its increased dislocation density and internal stress. Additionally, the presence of high-energy defects provides abundant active sites for the redeposition of Cu-bearing particles, while their uneven distribution further exacerbates corrosion. Therefore, we propose a competitive mechanism that governs the corrosion behavior of martensite, complementing the understanding of its behavior and mechanism.

Integrating additive manufacturing (AM) into polymer extrusion offers process chain flexibility and design freedom. It reduces the need for time-consuming iterations and trial-and-error in the die design process. Consequently, polymer AM of extrusion (i.e., soft tooling) allows for a shorter product development cycle and cost-effectiveness for small-scale production and highly customized products. In this study, carbon fibre (CF)-polyether-ether-ketone (PEEK) dies were manufactured using the fused filament fabrication (FFF) AM process, employing a streamlined die design achieved through freeform transition planes. Calibration slides were produced using masked stereolithography (MSLA), FFF, and conventional manufacturing techniques (i.e., machining) to preserve the final product’s cross-section during the cooling process. The dimensional and surface characteristics of these calibration slides were evaluated to assess the dimensional accuracy and surface topography of various materials and manufacturing processes. The dimensional evaluation reveals that MSLA-printed parts exhibit deviation from the nominal dimension closer to the conventionally manufactured part. The integrated soft tooling in the polymer extrusion line was tested with polypropylene (PP) and acrylonitrile butadiene styrene (ABS) as extruded materials. The surface topography of the CF-PEEK die displays distinctive ripple features resulting from the FFF process, identified by relatively flat peaks and deep valleys. The overall surface texture parameter values of CF-PEEK were higher due to the presence of deep valleys. Considering that the areas around the peaks interacted more with polymer molecules during the extrusion, the surface texture parameters of the extrudates were closer to the value observed in 90 µm region areas around the peaks. Notably, extrudates of AM calibration slides have lower surface texture parameters than extrudates of conventionally manufactured calibration slides, even though surface defects in the form of dimple sink marks were observed in extruded material of PP from extrudates using AM calibration slides.

The repeated melting and solidification cycles in the laser powder bed fusion (L-PBF) process lead to significant thermal gradients, resulting in notable distortion in the as-built part. Distortion compensation methods, which pre-deform the part design so the as-built shape aligns with the target, have been widely adopted to mitigate this issue. This research introduces a data-driven distortion compensation framework for the L-PBF process. It employs an experimentally-calibrated inherent strain method to generate a dataset and utilizes Gaussian process regression to create the compensated geometry. Experimental validation shows that the proposed method can reduce the maximum distortion by up to 82.5% for a lattice structure and 77.8% for a canonical part. Furthermore, the compensation results reveal that (1) the lumped layer thickness in finite element models has little impact on simulated distortion reduction but can notably affect the experimental reduction; (2) discrepancies between simulated and experimental compensation performance are largely attributed to the curvy surfaces with sharp transitions in trial and compensated shapes, a result of pre-deforming the design; (3) the number of trial geometries considerably affects the effectiveness of compensation, while the number of deformation states does not have a statistically significant impact.

In this study, we produced both homogeneous and heterogeneous-structured 316L austenitic stainless steels (SSs), each exhibiting comparable levels of yield strength (YS). Despite their similar YS, the heterogeneous-structured 316L SS exhibits a significantly higher tensile strength of ∼1 GPa compared to the homogeneous-structured 316L SS (∼832 MPa), and slightly higher fracture strain. The enhanced tensile strength and work hardening behavior in the heterogeneous-structured 316L SS were mainly attributed to the hetero-deformation induced (HDI) hardening, accelerated deformation-induced martensitic transformation (DIMT), and the presence of the nano-sized σ-phase particles. Our findings provide insights into the development of metastable heterogeneous-structured face-centered cubic (FCC) metallic materials with outstanding mechanical properties.

State-of-the-art Ni/Ti supermirror neutron optics have limited reflected intensity and a restricted neutron energy range due to the interface width. Incorporating low-neutron-absorbing ¹¹B₄C enhances reflectivity and allows for thinner layers to be deposited, with which more efficient supermirrors with higher m-values can be realized. However, incorporating ¹¹B₄C reduces the optical contrast, limiting the attainable reflectivity at low scattering vectors, making this approach infeasible. This study explores various approaches to optimize the material design of ¹¹B₄C-containing Ni/Ti supermirrors to maintain high reflectivity at low scattering vectors and achieve low interface widths at large scattering vectors. The scattering length density contrast versus interface width is investigated for multilayer periods of 30 Å, 48 Å, and 84 Å, for designs involving pure Ni/Ti multilayers, multilayers with ¹¹B₄C co-deposited in Ni and Ti layers, multilayers with ¹¹B₄C co-deposited only in Ni layers, and multilayers with ¹¹B₄C as thin interlayers between Ni and Ti layers. Our results suggest that a depth-graded hybrid material design by incorporating ¹¹B₄C inside the Ni and Ti layers, below approximately 26 Å, and introducing 1.5 Å ¹¹B₄C interlayers between the thicker Ni and Ti layers can achieve a higher reflectivity than state-of-the-art Ni/Ti multilayers over the entire scattering vector range.