1,721,137 research outputs found
Progress of flake powder metallurgy research
No full textThis paper reviewed several recent progresses of the new powder metallurgy technology known as flake powder metallurgy (FPM) including different processing routes, conventional FPM (C-FPM), slurry blending (SB), shift-speed ball milling (SSBM), and high-shear pre-dispersion and SSBM (HSPD/SSBM). The name of FPM was derived from the use of flake metal powders obtained by low-speed ball milling (LSBM) from spherical powder. In this case, the uniformity of reinforcement distribution leads to increased strength and ductility. Powder is the basic unit in PM, especially advanced PM, and its control is key to various new PM technologies. The FPM is a typical method for finely controlling the powder shape through low-energy ball milling (LEBM) to realize the preparation of advanced material structures. The present paper represents a review of the main results of research on FPM and indicates the potential for future studies devoted to the optimization of this processing route
Effect of bimodal grain structure on the microstructural and mechanical evolution of al-mg/cnts composite
No full textThe Al-Mg alloy structure reinforced with carbon nanotubes was evaluated after the composites production through a modified flake metallurgy technique followed by hot extrusion. The obtained bimodal microstructure of the matrix allowed to identify the microstructural mechanisms leading to high strength; uniform elongation and strain hardening ability of the produced composites. The presence of Mg transformed the native Al2O3 layer into spinel MgAl2O4 nano-phases dispersed both inside CG and UFGs and on the interfaces, improving the interfacial bonding of Al-Al as well as Al-CNT. The effect of the reinforcing phases percentages on the dislocations mechanisms evolution was evaluated through stress relaxation tests leading to the underlying of the effect of reinforcing phases on the modification of the interphase influence zone
Making ultra-high strengthening and toughening efficiency in hybrid reinforcing of aluminum laminated composites via dispersion engineering
Full text linkTo overcome the strength-ductility trade-off dilemma, herein we propose a hybrid in-situ/ex-situ reinforced aluminum matrix composite to achieve a uniform dispersion of reinforcements and strong reinforcement-matrix interfacial bonding. To exploit the pros of inter/intra granular dispersion of reinforcements, nano- Al3BC particles have been in-situ synthesized into ultrafine-grained (UFG) Al grain interior reinforced by carbon nanotubes (CNTs) via an elemental powder mixture, mechanical activation and subsequent annealing process. The in-situ nano-scaled Al3BC were uniformly distributed inside the elongated ultrafine Al grains, enabling stronger dislocation pinning and retention, providing stronger effective stress which consequently helps to enhance strength and strain hardening. The as-fabricated (Al3BC, CNT)/UFG Al exhibits simultaneous enhancement in strength (394 MPa) and total elongation (19.7 %) compared with its counterpart without the nano-Al3BC, suggesting the promising strengthening effects of in-situ/ex-situ reinforcing benefitting from the uniform dispersion and the strong semicoherent interface with the matrix
CNTs reinforced Al-based composites produced via modified flake powder metallurgy
No full textThe bimodal Al–Mg alloy structure reinforced with carbon nanotubes was evaluated after the composites production through a modified flake metallurgy technique followed by hot extrusion. The obtained bimodal microstructure of the matrix allowed to identify the microstructural mechanisms, leading to high strength, uniform elongation and strain hardening ability of the produced composites. The effect of the reinforcing phases percentages on the dislocations mechanisms evolution was evaluated through stress relaxation tests, leading to the underlying of the effect of reinforcing phases on the modification of the interphase influence zone. The results revealed that the deformation mechanism for unreinforced Al–Mg materials was forest dislocation cutting, whereas for CNT reinforcing Al–Mg composite was grain boundary and interface mediated straining. In fact, for Al–Mg/CNT composite, a task allocation occurred during the deformation process, namely at the early deformation stage by forest dislocation cutting and afterward at later deformation stage by dislocation/grain boundary/interface interaction
Effect of Al2O3, SiO2 and carbon nanotubes on the microstructural and mechanical behavior of spark plasma sintered aluminum based nanocomposites
No full textSpark plasma sintering (SPS) has been recognized, in the recent past, as a very useful method to produce metal matrix composites with enhanced mechanical and wear properties. Obviously, the materials final properties are strongly related to the reinforcement types and percentages as well as to the processing parameters employed during synthesis. The present paper analyses the effect of the addition of 2 wt% of Al2O3, SiO2 and carbon nanotubes (CNTs) on the mechanical and microstructural behavior of Al-based metal matrix composites produced via SPS. The results show that porosity and mechanical properties are strongly related to the reinforcement type. In particular a strong beneficial effect is revealed by Al2O3 nano particles and CNTs because of the optimal reinforcement dimensions
Design strategies for enhancing strength and toughness in high performance metal matrix composites: A review
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Architecture dependent strengthening mechanisms in graphene/Al heterogeneous lamellar composites
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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