查看更多>>摘要：The primary focus during surgery is to ensure successful implantation by achieving long-term and stable fixation of implants.Orthopaedic surgery is now more focused on the development of novel biomaterials intended to improve implant perfor-mance.To obtain a better understanding of metal implants,this article investigated the causes of material failures in certain cases and analysed a few case studies.The interaction between the implant and bone tissue was a crucial aspect of successful implantation,and this study explored the factors influencing this interaction as well as ways to improve it.Several modern approaches used for modifying implant surfaces were systematically illustrated and briefly analysed.Thermal spray coatings were often favoured because of their wide range of coating materials,but other substantial surface modifications(such as friction stir processing and laser surface texturing)were also used for a selection of applications.Notably,implant surfaces with desirable features,such as biocompatibility,antibacterial properties,corrosion resistance,and wear resistance,were essential for optimising implant functionality.This systematic review's main aim is to provide exhaustive reference informa-tion and a broad overview to advance the production and design of orthopaedic implants.
Ying ShenXianfeng ShanIniobong P.EtimMuhammad Ali Siddiqui...
242-254页
查看更多>>摘要：This research systematically examined the degradation,antibacterial effects,and biocompatibility of micro-arc oxidation(MAO)coatings with nano CuO and ZnO on extruded Mg alloys.Both copper(Cu)and Zinc(Zn)possess antibacterial properties.The findings demonstrated that adding ZnO will appreciably reduce the degradation rate of MAO-coating alloy due to the self-sealing micro holes.CuO+MAO coating exhibited excellent antibacterial performance,with an antibacterial rate of over 90％within 6 h co-cultured with Staphylococcus aureus.Similarly,the antibacterial rate of ZnO+MAO coating reached 90％after 12 h co-culture.Cytotoxicity test using MG63 cell indicated that the incorporation of CuO and ZnO did not notably affect the cell viability rate of the coating.Moreover,after 14 days of culture,the CuO+MAO and ZnO+MAO coated samples exhibited higher alkaline phosphatase(ALP)activity than the MAO-coated and uncoated samples,suggest-ing favorable osteogenic properties.
查看更多>>摘要：A Cu-10wt％Fe composite was prepared through hot-pressed sintering,and the material was subsequently solution treated.The hot-pressed sintered and solution treated materials were rolled and aged.The precipitation behavior and performance changes were systematically studied by using scanning electron microscopy and transmission electron microscopy.In con-trast to the hot-pressed sintered specimen,the solution treatment significantly affects the thermal stability and properties of the Cu-10wt％Fe composite.The Cu-10wt％Fe composite was prepared after solid solution,cold rolling and aging at 773 K for 1 h,and it obtained excellent tensile strength of 494 MPa,uniform elongation of 16.3％,electrical conductivity of 51.1％IACS and softening temperature of 838 K.Mechanisms for the distinct difference in thermal stability and properties between hot-pressed sintered and solution treated specimens were analyzed.These findings provide a theoretical basis for designing high-performance Cu-based in-situ composites by post treatment.
查看更多>>摘要：Effect of direct aging of 170 ℃ on corrosion behavior of laser powder bed fused AlSi10Mg(LPBF-AlSi10Mg)was studied by microstructure analysis,electrochemical analysis and X-ray photoelectron spectrometer.The results show that direct aging of 170 ℃ has little effect on melt pool and Si cellular structure,but promotes the precipitation of nano-Si particles and releases the residual stress.With increasing aging time from 0 to 4 h to 24 h,the corrosion property of the LPBF-AlSi10Mg is deterio-rated,which is evidenced by increased corrosion current density and decreased pitting potential and polarization resistance.With increasing the aging time,the thickness of the oxide film formed on surface of the LPBF-AlSi10Mg increases.The Si content of the oxide film of the sample aging for 4 h is the lowest,9.42 at.％,and it is the highest,18.62 at.％,for the sample aging for 24 h.The electrochemical noise analysis reveals that the middle-frequency contribution of the Hilbert spectrum is responsible for the deteriorated corrosion performance,which corresponds to metastable pitting initiated by nano-Si particles.
查看更多>>摘要：The hot compression behavior and tensile strength after compression of a new Ni-Co-based superalloy produced using elec-tron beam smelting layered(EBSL)solidification technology were investigated.Isothermal compression tests were performed at temperatures of 1120 ℃ and 1150 ℃,with strain rates of 1 s-1 and 0.01 s-1,reaching a true strain of 0.51.Tensile strength was evaluated at room temperature.The results revealed that this EBSL technology accelerates dynamic recrystallization(DRX),without compromising the strength of alloy.A significant correlation between the volume fraction of DRX and the strain rate was observed,with higher fractions at lower strain rates,leading to higher tensile strength.Additionally,at the same strain rate,the specimens compressed at 1120 ℃ exhibited higher tensile strength due to undissolved γ'precipitates.After solution and aging heat treatment,the alloy maintained high tensile strength.The results suggested that the EBSL Ni-Co-based superalloy offers excellent prospects for practical applications.
查看更多>>摘要：The effects of hydrogen charging time and pressure on the hydrogen embrittlement(HE)susceptibility of X52 pipeline steel material are studied by slow strain rate tensile tests.The fracture morphologies of the specimens are observed by scanning electron microscopy.The HE susceptibility of the X52 pipeline steel material increases with an increase in both hydrogen charging time and hydrogen pressure.At a charging time of 96 h,the HE susceptibility index reaches 45.86％,approximately 3.6 times that at a charging time of 0 h.Similarly,a charging pressure of 4 MPa results in a HE susceptibility index of 31.61％,approximately 2.5 times higher than that at a charging pressure of 0.3 MPa.
查看更多>>摘要：The corrosion behavior and mechanism of 3Ni weathering steel in a simulated oceanic atmospheric environment are investi-gated in order to comprehend the impacts of La,as determined through electrochemical analysis and rust layer characteriza-tion.The results of this study demonstrate that the addition of La enhances the corrosion resistance of 3Ni weathering steel in the marine atmospheric environment,thereby reducing the corrosion rate and improving the protection of the rust layer.The influence of La on corrosion resistance can be attributed to two primary factors.Firstly,La functions as a grain refiner,minimizing the potential difference of the micro-regions on the substrate surface,thereby significantly reducing the corro-sion of bare steel in the marine environment.Secondly,La inhibits the process of Fe3O4 oxidation back to γ-FeOOH during corrosion at the local site,thus decreasing the formation of γ-FeOOH and enhancing the charge transfer resistance.This research work may serve as a reference for expanding the application of rare earth elements in the field of weathering steel.
查看更多>>摘要：The effect of multiphase microstructure in the center segregation zones(CSZ)of high-strength steel thick plates on work hard-ening characteristics and crack initiation/propagation were studied.Microstructure was correlated with deformation damage behavior by using Taylor factor(TF)gradients,kernel average misorientation(KAM),and geometric necessary dislocation(GND)density.The results show that the segregation leads to a mixed structure of ferrite(soft phase)and martensite/bainite(hard phase)in the center of the thick plate.Compared to the 1/4 thickness(1/4 T)region,grain refinement occurred in the CSZ,with KAM values increasing from 0.24 to 0.49 and a decrease in the proportion of high-angle grain boundaries(＞15°)from 77.4 to 51.8％.In the process of deformation,due to the influence of grain refinement and adjacent martensite/bainite,ferrite grains were divided into structural units with different TF values.The higher KAM value and GND density at the interface between soft/hard phases resulted in severe work hardening.In addition,the presence of micron-sized inclusions in the CSZ caused local strain concentration and non-continuous deformation of the matrix,which induced crack initiation.The fracture surface showed a mixed mode of brittle cleavage fracture and ductile fracture.
查看更多>>摘要：AZ31/Mg3Y composites with a layer thickness of 100-200 μm were fabricated by accumulated rolling bonding(ARB),which was followed by diffusion annealing at 300 ℃ for 0-32 h.An interface layer,containing numerous Al-Y precipitates,is formed in the Mg3 Y layer that is adjacent to the interface as a result of Al diffusing from the AZ31 layers into the Mg3 Y layers.The thickness of the interface layer gets increased and more precipitates are formed in the interface layer with the extension of the annealing time.The microhardness of the AZ31 and Mg3 Y layer decreases firstly and then reaches a sta-ble value,while the microhardness of the interface layer increases gradually with the extension of the annealing time.The AZ31/Mg3Y composites exhibit equivalent strength but increased ductility after diffusion annealing,in comparison to the as-rolled AZ31/Mg3Y composite.In addition,the AZ31/Mg3Y composites after annealing always present higher strength and ductility than AZ31/AZ31 composite,which was fabricated by the same process as that for the AZ31/Mg3Y composites.Hetero-deformation induced strengthening also plays an important role in the excellent strength and ductility of the annealed AZ31/Mg3Y composite.This study can provide a direction for improving the plasticity and strength of magnesium alloys synergistically.
查看更多>>摘要：Superplastic forming is a practical method to manufacture complex-shaped parts of titanium alloys with large deforma-tion.Laminated parts of dissimilar titanium alloys fabricated by superplastic forming can achieve excellent performance by combining the advantages of components.This work displays the superplastic tension behavior and microstructural evolution of dissimilar TC4/SP700 laminate prepared by the diffusion bonding process.Two titanium alloys can achieve metallurgical bonding at parameters of 800 ℃/l h/5 MPa.Except for dynamic recrystallization and grain growth behaviors upon superplastic tension,stress-induced phase transformation plays an important role in a to β phase transformation apart from the elevated temperature.The superplastic deformation can be attributed to the grain boundary sliding accommodated multiplex motion of dislocations.In addition,the retained strengths of all dissimilar TC4/SP700 laminates after superplastic deformation with different strain rates and temperatures range from 807 to 890 MPa.
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