Chemically Modified Sugarcane Bagasse for Innovative Bio-Composites. Part One: Production and Physico-Mechanical Properties

Sugarcane bagasse is an agro-waste that could replace timber resources for the production of bio-composites.Composite boards such as particleboard offer an issue for the use and recycling of poor quality timber,and these engineered products can overcome some solid wood limitations such as heterogeneity and dimension.Bagasse offers an alternative to wood chips for particleboard production but present some disadvantages as well,such as poor physico-mechanical properties.To address these issues,bagassefibers were treated with an innovative natural resin formulated with tannin and furfural.Impregnated particles with different concentrations of resin(5%,10%,and 15%m/m)were exposed to temperatures of 40°C,60°C,80°C,and 100°C for resin curing.Various types of tannin-based adhesives,including tannin formaldehyde,tannin/formaldehyde-furfural,and tannin hex-amine,were utilized for bonding the treated bagasse particles.The resultant panels were assessed for their physical and mechanical properties and compared to those produced using Melamine-Urea-Formaldehyde(MUF)adhe-sive.The density of the panels varied from 650 to 730 kg/m3 depending on the resin concentration.The values for both modulus of elasticity and modulus of rupture increased as the resin concentration increased.The internal bonding values exhibited an increase with resin concentration up to a critical point,after which a decreasing trend was observed.The water absorption and thickness swelling were significantly reduced with an increase in resin concentration.However,the panels produced using MUF adhesive yielded the most favorable physico-mechanical properties.Additionally,the panels made with tannin-based adhesives met the minimum requirements specified in the standard EN 312(specifications for uncoated resin-bonded particleboards)for application in dry condi-tions.The analysis of formaldehyde emissions indicated that panels produced with tannin-based adhesives exhib-ited significantly lower emissions compared to those made with MUF.The tannin/furfural resin showed great potential for improving the quality of bagasse particleboard using tannin-based adhesives.

Influence of Plastic and Coconut Shell (Cocos nucifera L.) on the Physico-Mechanical Properties of the 8/6 Composite Rafter

In this paper, the authors aim to propose the use of waste plastics as a binder in a coconut shell reinforcement for the development of an 8/6 size composite rafter to replace the natural 8/6 size backbone in construction. Following a study into the choice of the best proportions, a total of 30 size 8/6 composite rafters with different proportions of 20%, 25%, 30%, 35%, 40% and 50% plastic content were developed. All the 8/6 composite rafters were subjected to mechanical (3-point bending strength and Monnin hardness) and physical (bulk density and water absorption) characterization analyses. The results show that flexural strength increases from 27.56 MPa to 33.30 MPa for proportions ranging from 20% to 35% plastic content. Above 35% plastic, the strength drops to 19.60 MPa for a 50% plastic content. Similarly, the Monnin hardness drops from 9 mm to 5 mm when the plastic content varies from 20 to 50%. As for the results of the physical characterisation, the values obtained for apparent density vary from 0.89 to 1 for proportions varying from 20% to 35% plastic content and drop to 0.94 for 50% plastic content. As for water absorption, values drop from 6.82% to 2.45% when the plastic content increases from 20% to 50%. These mechanical strengths stabilise at 35% plastic content. The development of an 8/6 chevron composite material based on plastic and coconut shell could therefore be a way of recovering waste and solving the problem of deforestation.

Effects of temperature and age on physico-mechanical properties of cemented gravel sand backfills

Cemented backfill used in deep mines would inevitably be exposed to the ambient temperature of 20−60℃in the next few decades.In this paper,two types of cemented gravel sand backfills,cemented rod-mill sand backfill(CRB)and cemented gobi sand backfill(CGB),were prepared and cured at various temperatures(20,40,60℃)and ages(3,7,28 d),and the effects of temperature and age on the physico-mechanical properties of CRB and CGB were investigated based on laboratory tests.Results show that:1)the effects of temperature and age on the physico-mechanical properties of backfills mainly depend on the amount of hydration products and the refinement of cementation structures.The temperature has a more significant effect on thermal expansibility and ultrasonic performance at early ages.2)The facilitating effect of temperature and age on the compressive strength of CGB is higher than that on CRB.With the increase of temperature,the compressive failure modes changed from X-conjugate shear failure to tensile failure,and the integrity of specimens was significantly improved.3)Similarly,the shear performance of CGB is generally better than that of CRB.The temperature has a weaker effect on shear strength than age,but the shear deformation and shear plane morphology are closely related to temperature.

Physico-mechanical properties of granite after cyclic thermal shock

Understanding rock mechanical behaviors after thermal shock is critically important for practical engineering application.In this context,physico-mechanical properties of Beishan granite,Gansu Province,China after cyclic thermal shock were studied using digital image correlation(DIC),acoustic emission(AE)monitoring,and microscopic observation.The results show that the peak strength and elastic modulus decreased gradually with increase in thermal shock cycle.However,the above two parameters showed no further changes after 10 thermal shock cycles.The loading stress ratio(i.e.the ratio of the current loading stress level to the peak stress in this state)corresponding to the occurrence of the uneven principal strain field and the local strain concentration zone on the surface of the granite specimen decreased with increase in thermal shock cycle.Three transformation forms of the standard deviation curves of the surface principal strain were found.For granite with fewer thermal shock cycles(e.g.no more than 2 cycles),the standard deviation curves exhibited approximately exponential growth in exponential form.With increase in thermal shock cycle,the S-shaped curve was dominant.After 10 thermal shock cycles,an approximate ladder-shaped curve was observed.It is displayed that AE activity was mainly concentrated around the peak strength zone of the granite specimen when the rock samples underwent fewer thermal shock cycles.With increase in thermal shock cycle,AE activity could occur at low loading stress levels.Microscopic observation further confirmed these scenarios,which showed that more microcracks were induced with increase in thermal shock cycle.The number of induced microcracks at the edge location of the granite specimen was significantly larger than that at the interior location.Finally,a continuum damage model was proposed to describe the damage evolution of the granite specimen after cyclic thermal shock during loading.

Experimental study on the physico-mechanical properties of Tamusu mudstone — A potential host rock for high-level radioactive waste in Inner Mongolia of China

Tamusu mudstone, located in Bayin Gobi Basin in Inner Mongolia of China, has been selected as a potential host rock for high-level radioactive waste(HLW) disposal in China. A series of tests has been carried out, including X-ray diffraction(XRD) tests, scanning electron microscopy(SEM) tests, disintegration tests, permeability tests and triaxial compression tests, to estimate the physico-mechanical properties of Tamusu mudstone in this work. The mineral composition of Tamusu mudstone was analyzed and it was considered as a stable rock due to its low disintegration rate, i.e. approximately 0.11%after several wet/dry cycles. Based on the results of permeability test, it was found that Tamusu mudstone has a low permeability, with the magnitude of about 10—20m^(2). The low permeability makes the mudstone well prevent nuclide migration and diffusion, and might be influenced by temperature.The triaxial tests show that Tamusu mudstone is a stiff mudstone with high compressive strength, which means that the excavation disturbed zone would be smaller compared to other types of mudstone due to construction and operation of HLW repositories. Finally, the properties of Tamusu mudstone were compared with those of Opalinus clay, Callovo-Oxfordian(COx) argillite, and Boom clay to further discuss the possibility of using Tamusu mudstone as a potential nuclear waste disposal medium.

The Relationship between Microtexture Types and Indices of Physico-Mechanical Properties of Loess in China

The paper deals mainly with the relationship between the microtexture types and the indices of physicomechanical properties of loess. The results of study demonstrate that the study of microtextures of loess is of importance in the prediction and preliminary evaluation of engineering geological properties of loess in a region.

Effect of Substitution of Cement by Mineral Powders on the Physico-mechanical Properties and Microstructure of Sand Concretes

The approach that contributes to the development of eco-materials in construction is the use of mineral powders,which can improve mechani­cal properties and reduce cement consumption.This article aims to study the effect of substitution by mass of cement with mineral powders on the physicomechanical properties and microstructure of sand concretes.The used mineral powders are A:the limestone,B:the natural pozzolan,C:the hydraulic lime,D:(1/3 limestone+1/3 natural pozzolan+1/3 hydraulic lime),and E:(1/2 natural pozzolan+1/2 hydraulic lime).The studied percentages are 5%,10%and 15%,in both separated and combined states.The studied properties are workability,compressive strength,the elastic­ity modulus in compression,shrinkage and microstructure analysis.The objective is to target the optimal percentage of the substitution of cement with mineral powders,which ensures the best compromise between the main properties of the studied sand concretes.The obtained results show that the optimal percentage is in favor of the substitution of cement by 10%D(1/3 limestone,1/3 natural pozzolan and 1/3 hydraulic lime).Even the 15%of mineral powder D,presented similar performances compared to the sand concrete(without mineral powders).Finally,in the context of the development of eco-materials,it should be noted that the 10%D and 15%D(1/3 limestone,1/3 natural pozzolan and 1/3 hydraulic lime)contribute to decrease the use of cement and consequently to reduce of CO2 emissions.

Relationship between Physico-Mechanical Properties, Compacting Pressure and Mixing Proportion of Briquettes Produced from Maize Cobs and Sawdust

This study examined the relationship between selected physico-mechanical properties, compacting pressure and mixing proportion of briquettes produced from combination of maize cob particles and sawdust of low, medium and high density timber species. Particle sizes of maize cobs and sawdust used for the study were ≤1 mm. The two materials were combined at mixing percentages of 90:10, 70:30 and 50:50 (Sawdust:maize cobs). Briquettes were produced at room temperature (28°C) using compacting pressures 20, 30, 40 and 50 MPa. The results suggested that combining maize cob particles with sawdust of low, medium and high density wood species could significantly enhance the relaxed density, compressive strength in cleft and impact resistance index of briquettes produced from agricultural biomass residue like maize cobs. The results further indicated that the physical and mechanical characteristics of briquettes produced from combinations of sawdust of low density species and maize cobs were exceptionally higher than that produced from combinations of maize cob particles, and medium density and high density timber species. The R2 values for the regression model between the independent variables (mixing percentage and compacting pressure) and relaxed density, compressive strength in cleft and impact resistance index of briquettes produced from combinations of maize cob particles and sawdust of low density species (Ceiba pentandra) were 0.966, 0.932 and 0.710 respectively. This study provides a hope for briquetting maize cobs at room temperature using a low compacting pressure.

Physico-Mechanical Properties of Bio-Based Bricks

The aim of this work is to improve the high performance of mud bricks. The latter was reinforced with rice straws as stabiliser leading to an improvement of the physico-mechanical properties. Thus, the physical characteristics of the clay such as natural water content, density, atterberg limit, plasticity limit (Wp) and plasticity index (Ip) were determined. Their values are respectively 8.39%, 2025.73 Kg/m3, 47.66%, 29.75% and 17.91%. The clay used is a low plastic organic silt. The normal proctocol provided an optimum dry density (ɣOP) of 1.28 Kg/m3 at an optimum moisture content of 12.42%. The actual density of the straw is 464 Kg/m3, its absorption rate reached 206% in 5 mins and stabilised at 385% at 480 mins of immersion. The maximum bending and compression strengths are respectively 1.52 and 0.164 MPa. The mud brick absorption coefficients obtained are between 4.875 at 0% straw and 20.573% at 3% straw.

Effect of Alumina Particles Addition on Physico-Mechanical Properties of AL-Matrix Composites

Metal-matrix composites (MMCs) are attracting considerable interest worldwide because of their superior mechanical and tribological properties. This study describes multifactor-based experiments that were applied to research and investigates Aluminum matrix composite reinforced with 5, 10 & 15 wt% Alumina particles. Mechanical mixing technique was used for fabrication. Sintering was carried out in a vacuum furnace at 600°C for 1 hr. The effects of Alumina percentage on the density, microstructure, both electrical & thermal conductivities, hardness and compression strength was investigated. The results showed that sample containing 5 wt% Alumina is near-fully dense. Also it has the highest hardness and compression strength.

Effect of TiO2 Filler Loading on Physico-Mechanical Properties and Abrasion of Jute Fabric Reinforced Epoxy Composites

Mechanical properties and abrasive wear behaviour of bi-directional jute fabric reinforced epoxy (J/Ep) with micron sized TiO2 particles at different wt% (2.5, 5, 7.5 and 10) were investigated. The tribo-potential of combined effect of TiO2 and jute fiber in epoxy (J/Ep) for enhancing the abrasion resistance has not been studied so far. Hence, the present work aims to explore the possibility of using TiO2 filler and jute fiber to reinforce the epoxy and thus open a new way to implement inexpensive reinforcements and produce new candidate tribo-material for industrial applications. Silane treated TiO2 filled J/Ep composites were prepared by hand lay-up method. Selected mechanical properties and three-body abrasive wear tests were evaluated as per ASTM standards. Results indicate an enhancement in the J/Ep composite mechanical properties due to addition of TiO2 particles up to 7.5 wt% of loading. Highest tensile and flexural properties were found at 7.5 wt% TiO2 loading. Results of abrasion tests show resistance to abrasion at 5 wt% TiO2 filled J/Ep composite. Scanning electron micrographs evidenced that the fiber and filler have fairly good bonding with matrix. Finally, this investigation confirms the applicability of TiO2 as secondary reinforcement in J/Ep composite.

Understanding the Effect of Zinc Oxide(ZnO)With Carbon Black Coupling Agent on Physico-Mechanical Properties in Natural Rubber Matrix

Natural rubber(NR)is not only the main compounding ingredient used to make the majority of components of tires as well as other rubber products,as it plays a significant role in ensuring that they operate well and complies with environmental standards.The applications of NR products are lim-ited to high temperatures due to the revision tendency of NR vulcanizate.To address these issues,the potential engagement of a carbon black(CB)coupling agent(CA)in the presence of metal oxide i.e.Zinc Oxide(ZnO)was investigated in an NR-based system.This CA has dual functionality on physicomechanical properties.CA has the ability to reduce hysteresis loss as well as improve anti-reversion properties and these properties thorough-ly depend on the presence of ZnO.While ZnO was added to the master formulation,a 65%improvement in reversion properties was observed.On the other hand,while ZnO fully transferred to the final formulation,bound rubber(BR)content increased by 19%,the difference in storage modulus(ΔG’)is reduced by 22%,cure rate index(CRI)improved by 14%,loss tangent(tanδ)reduced by 18%and slightly improve in elongation at break compared to control compound.Thermo-gravimetric analysis(TGA)was engaged to understand the thermal stability and degree of purity of CA.A differential Scanning Calorimeter(DSC)was used to detect the phase tran-sition of CA.Fourier Transform Infrared Spectrum(FTIR)was adopted to detect the presence of carboxyl and amine groups in the CA moiety.Payne effect,BR content and Transmission Electron Microscope(TEM)were em-ployed to investigate the micro-level dispersion of CB in the natural rubber(NR)matrix.

Impact of Mixed Fillers on the Physico-mechanical Properties of Flex­ible Polyether Foam

The effect of proportional blend of periwinkle and African star apple seed shell as bio-fillers in flexible polyether foam was studied.Flexible polyether foam samples incorporated with these bio-fillers at varying percentages;10%(S1),20%(S2),30%(S3),40%(S4)and 50%(S5)were produced respectively,while 0%(S0)which had no filler was used as control during the experiment.The mechanical properties of the produced foam samples were determined via density,compression set,indentation hardness,tensile strength and elongation at break tests.The cream time,rise time and height of the foam as parameters for characterising the produced foam samples were determined too.Flammability test was also carried out.The microstructure of the foam samples was analysed as well by using the scanning electron microscope.The results of the experiment showed that the density of the foam samples progressively increased from 19.20(S0)-26.45(S5)as the quantity of the filler increased.The indentation hardness result also showed an increase on addition of the filler.The foam’s loading ability also increased on incorporation of the filler but S3 showed remarkable recovery after compression.The tensile strength and elongation at break of the foam decreased on addition of the filler.The morphological analysis ascertained the effect of the progressive introduction of the filler on the surface morphology of the foam.The flammability of the foam was found to decrease as the filler load increased.Since these fillers are of organic origin,readily available,cheap and eco-friendly,they provide a means of making biodegradable foam,and reducing the flammability of foam.Thus,reducing environmental pollution whilst enhancing the mechanical property of foam.

Composite Panels from the Combination of Rice Husk and Wood Chips with a Natural Resin Based on Tannins Reinforced with Sugar Cane Molasses Intended for Building Insulation: Physico-Mechanical and Thermal Properties

The objective of this work is to develop new biosourced insulating composites from rice husks and wood chips that can be used in the building sector. It appears from the properties of the precursors that rice chips and husks are materials which can have good thermal conductivity and therefore the combination of these precursors could make it possible to obtain panels with good insulating properties. With regard to environmental and climatic constraints, the composite panels formulated at various rates were tested and the physico-mechanical and thermal properties showed that it was essential to add a crosslinker in order to increase certain solicitation. an incorporation rate of 12% to 30% made it possible to obtain panels with low thermal conductivity, a low surface water absorption capacity and which gives the composite good thermal insulation and will find many applications in the construction and real estate sector. Finally, new solutions to improve the fire reaction of the insulation panels are tested which allows to identify suitable solutions for the developed composites. In view of the flame tests, the panels obtained are good and can effectively combat fire safety in public buildings.

Microstructures,corrosion behavior and mechanical properties of as-cast Mg-6Zn-2X(Fe/Cu/Ni)alloys for plugging tool applications

Mg-6Zn-2X(Fe/Cu/Ni)alloys were prepared through semi-continuous casting,with the aim of identifying a degradable magnesium(Mg)alloy suitable for use in fracturing balls.A comparative analysis was conducted to assess the impacts of adding Cu and Ni,which result in finer grains and the formation of galvanic corrosion sites.Scanner electronic microscopy examination revealed that precipitated phases concentrated at grain boundaries,forming a semi-continuous network structure that facilitated corrosion penetration in Mg-6Zn-2Cu and Mg-6Zn-2Ni alloys.Pitting corrosion was observed in Mg-6Zn-2Fe,while galvanic corrosion was identified as the primary mechanism in Mg-6Zn-2Cu and Mg-6Zn-2Ni alloys.Among the tests,the Mg-6Zn-2Ni alloy exhibited the highest corrosion rate(approximately 932.9 mm/a)due to its significant potential difference.Mechanical testing showed that Mg-6Zn-2Ni alloy possessed suitable ultimate compressive strength,making it a potential candidate material for degradable fracturing balls,effectively addressing the challenges of balancing strength and degradation rate in fracturing applications.

Effects of deformation temperatures on microstructures,aging behaviors and mechanical properties of Mg-Gd-Er-Zr alloys fabricated by hard-plate rolling

In this investigation,a high-strength Mg-12Gd-1.0Er-0.5Zr(wt.%)alloy sheet was produced by hot extrusion(HE)and subsequent hard-plate rolling(HPR)at different temperatures.The results indicate that the microstructures of these final-rolled sheets are inhomogeneous,mainly including coarse deformed grains and dynamic recrystallized(DRXed)grains,and the volume fraction of these coarse deformed grains increases as the rolling temperature increases.Thus,more DRXed grains can be found in R-385℃sheet,resulting in a smaller average grain size and weaker basal texture,while the biggest grains and the highest strong basal texture are present in R-450℃sheet.Amounts of dynamic precipitation ofβphases which are mainly determined by the rolling temperature are present in these sheets,and its precipitation can consume the content of Gd solutes in the matrix.As a result,the lowest number density ofβphase in R-450℃sheet is beneficial to modify the age hardening response.Thus,the R-450℃sheet displays the best age hardening response because of a severe traditional precipitation ofβ’(more)andβH/βM(less)precipitates,resulting in a sharp improvement in strength,i.e.ultimate tensile strength(UTS)of∼518±17 MPa and yield strength(YS)of∼438±18 MPa.However,the elongation(EL)of this sheet reduces greatly,and its value is∼2.7±0.3%.By contrasting,the EL of the peak-aging R-385℃sheet keeps better,changing from∼4.9±1.2%to∼4.8±1.4%due to a novel dislocation-induced chain-like precipitate which is helpful to keep good balance between strength and ductility.

Pulsed current-assisted twelve-roll precision rolling deformation of SUS304 ultra-thin strips with exceptional mechanical properties

Innovative pulsed current-assisted multi-pass rolling tests were conducted on a 12-roll mill during the rolling deformation processing of SUS304 ultra-thin strips.The results show that in the first rolling pass,the rolling reduction rate of a conventionally rolled sample(at room temperature)is 33.8%,which can be increased to 41.5%by pulsed current-assisted rolling,enabling the formation of an ultra-thin strip with a size of 67.3μm in only one rolling pass.After three passes of pulsed current-assisted rolling,the thickness of the ultra-thin strip can be further reduced to 51.7μm.To clearly compare the effects of a pulsed current on the microstructure and mechanical response of the ultra-thin strip,ultra-thin strips with nearly the same thickness reduction were analyzed.It was found that pulsed current can reduce the degree of work-hardening of the rolled samples by promoting dislocation detachment,reducing the density of stacking faults,inhibiting martensitic phase transformation,and shortening the total length of grain boundaries.As a result,the ductility of ultra-thin strips can be effectively restored to approximately 16.3%while maintaining a high tensile strength of 1118 MPa.Therefore,pulsed current-assisted rolling deformation shows great potential for the formation of ultra-thin strips with a combination of high strength and ductility.

High-throughput calculations combining machine learning to investigate the corrosion properties of binary Mg alloys

Magnesium(Mg)alloys have shown great prospects as both structural and biomedical materials,while poor corrosion resistance limits their further application.In this work,to avoid the time-consuming and laborious experiment trial,a high-throughput computational strategy based on first-principles calculations is designed for screening corrosion-resistant binary Mg alloy with intermetallics,from both the thermodynamic and kinetic perspectives.The stable binary Mg intermetallics with low equilibrium potential difference with respect to the Mg matrix are firstly identified.Then,the hydrogen adsorption energies on the surfaces of these Mg intermetallics are calculated,and the corrosion exchange current density is further calculated by a hydrogen evolution reaction(HER)kinetic model.Several intermetallics,e.g.Y_(3)Mg,Y_(2)Mg and La_(5)Mg,are identified to be promising intermetallics which might effectively hinder the cathodic HER.Furthermore,machine learning(ML)models are developed to predict Mg intermetallics with proper hydrogen adsorption energy employing work function(W_(f))and weighted first ionization energy(WFIE).The generalization of the ML models is tested on five new binary Mg intermetallics with the average root mean square error(RMSE)of 0.11 eV.This study not only predicts some promising binary Mg intermetallics which may suppress the galvanic corrosion,but also provides a high-throughput screening strategy and ML models for the design of corrosion-resistant alloy,which can be extended to ternary Mg alloys or other alloy systems.

Transformation of long-period stacking ordered structures in Mg-Gd-Y-Zn alloys upon synergistic characterization of first-principles calculation and experiment and its effects on mechanical properties

Based on experiments and first-principles calculations,the microstructures and mechanical properties of as-cast and solution treated Mg-10Gd-4Y-xZn-0.6Zr(x=0,1,2,wt.%)alloys are investigated.The transformation process of long-period stacking ordered(LPSO)structure during solidification and heat treatment and its effect on the mechanical properties of experimental alloys are discussed.Results reveal that the stacking faults and 18R LPSO phases appear in the as-cast Mg-10Gd-4Y-1Zn-0.6Zr and Mg-10Gd-4Y-2Zn-0.6Zr alloys,respectively.After solution treatment,the stacking faults and 18R LPSO phase transform into 14H LPSO phase.The Enthalpies of formation and reaction energy of 14H and 18R LPSO are calculated based on first-principles.Results show that the alloying ability of 18R is stronger than that of 14H.The reaction energies show that the 14H LPSO phase is more stable than the 18R LPSO.The elastic properties of the 14H and 18R LPSO phases are also evaluated by first-principles calculations,and the results are in good agreement with the experimental results.The precipitation of LPSO phase improves the tensile strength,yield strength and elongation of the alloy.After solution treatment,the Mg-10Gd-4Y-2Zn-0.6Zr alloy has the best mechanical properties,and its ultimate tensile strength and yield strength are 278.7 MPa and 196.4 MPa,respectively.The elongation of Mg-10Gd-4Y-2Zn-0.6Zr reaches 15.1,which is higher than that of Mg-10Gd-4Y0.6Zr alloy.The improving mechanism of elastic modulus by the LPSO phases and the influence on the alloy mechanical properties are also analyzed.

Microstructure and damping properties of LPSO phase dominant Mg-Ni-Y and Mg-Zn-Ni-Y alloys

This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period stacked ordered(LPSO)phase in the two alloys during heat treatment was the focus.The morphology of the as-cast Mg_(95.34)Ni_(2)Y_(2.66)presented a disordered network.After heat treatment at 773 K for 2 hours,the eutectic phase was integrated into the matrix,and the LPSO phase maintained the 18R structure.As Zn partially replaced Ni,the crystal grains became rounded in the cast alloy,and lamellar LPSO phases and more solid solution atoms were contained in the matrix after heat treatment of the Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloy.Both Zn and the heat treatment had a significant effect on damping.Obvious dislocation internal friction peaks and grain boundary internal friction peaks were found after temperature-dependent damping of the Mg_(95.34)Ni_(2)Y_(2.66)and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys.After heat treatment,the dislocation peak was significantly increased,especially in the alloy Mg_(95.34)Ni_(2)Y_(2).66.The annealed Mg_(95.34)Ni_(2)Y_(2.66)alloy with a rod-shaped LPSO phase exhibited a good damping performance of 0.14 atε=10^(−3),which was due to the difference between the second phase and solid solution atom content.These factors also affected the dynamic modulus of the alloy.The results of this study will help in further development of high-damping magnesium alloys.