Coarse Morphology Research Articles

ABS/HIPS blends obtained from WEEE: Influence of processing conditions and composition

ABSTRACTThe recycling of acrylonitrile–butadiene–styrene (ABS) and high‐impact polystyrene (HIPS) from postconsumer electronic equipment housing was investigated. A preliminary study of shot size and particle size effects on the mechanical properties of ABS/HIPS (50/50) blends obtained directly via injection molding was conducted. Injection‐molded specimens of ABS/HIPS blends, obtained at different compositions with or without previous extrusion, were subjected to mechanical, thermal, and morphological testing. Preliminary studies showed that a smaller particle size resulted in higher tensile and impact strength, regardless of the shot size used during injection molding. ABS/HIPS blends obtained using previous extrusion presented a slight increase in Young's modulus and a decrease in elongation at break and impact strength. The increase in glass‐transition temperature related to the Polybutadiene (PB) phases of these blends indicated a possible increase in crosslinking structures during extrusion. In addition, these blends showed a coarse and heterogeneous morphology, suggesting that ABS did not completely mix with HIPS. Compared to processing conditions, the blend composition appeared to have a much stronger effect on the mechanical properties. The results obtained suggest the possibility of obtaining ABS/HIPS blends directly via injection molding as long as small ground particles are used. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43831.

Effect of nodule count and austempering heat treatment on segregation behavior of alloying elements in ductile cast iron

The equilibrium partition ratio, k, has been measured for Mn, Mo, Si, Ni and Cu in a ductile iron with composition (wt.%): 3.45C, 0.25Mn, 0.25Mo, 2.45Si, 0.5Ni and 0.5Cu with different nodule counts obtained from different section sizes of 13, 25, 75 mm in the as cast, austenitized (at 870 °C for times 1, 4 and 6 hours) and austempered (at 375 °C for times 1 to 1,440 min) samples. Results show that Mn and Mo segregate positively at cell boundaries, but Si, Ni and Cu concentrate in an inverse manner in the vicinity of graphite nodules and there is a depletion of these elements at cell boundaries. Segregation curves for Ni and Cu are more smooth than for Si. Carbide formation has been observed at cell boundaries. Based on the results, the partition ratios for all elements decrease with increasing the nodule count. More carbide with coarser morphology has been observed in the microstructure with a lower nodule count. Austenitization for a longer time can decrease partition ratio, but cannot eliminate it entirely. Increasing the austenitization temperature has the same efect. Austenitizing parameters have no significant effect on carbides volume fraction. The kinetics of austempering is faster in higher nodule counts and subsequently better mechanical properties including higher ductility, strength and toughness have been observed for all austempering conditions studied.

Rheo-Cast Microstructure and Mechanical Properties of AM60 Alloy Produced by Self-Inoculation Rheo-Diecasting Process

Rheo-forming is becoming the choice for production of high quality parts with diminished defects and fine integrity. In this paper, the novel self-inoculation rheo-diecasting (SIRD) process, in which semisolid slurry is produced by mixing two precursory solid and liquid alloys and subsequently pouring them through a multi-stream fluid director, has been proposed. Microstructural characteristics of AM60 alloy slurry and the microstructure and mechanical properties of rheo-diecasting AM60 samples were investigated. Quenching experiments reveal that the slurry microstructure of AM60 was well refined to irregular α-Mg particles with the average size of approximately 20–40 μm after pouring with the self-inoculation process, and these particles were evolved to globular and coarse morphology while continuously keeping in semisolid state. After rheo-diecasting, the microstructure of the sample was dominated by fine primary α-Mg globules accompanied with tiny secondary α-Mg particles while the sample from conventional liquid die casting was characterized by developed dendrite and porosity. Microscopic analysis indicates that there are three stages of remaining liquid solidification in die cavity in SIRD: α-Mg nucleation and growth on primary α-Mg surface, α-Mg nucleated independently in liquid, and, finally, formation of skeleton devoiced eutectic. Due to diminished porosity and hot tearing, tensile strength and elongation of SIRD samples were increased by 12.9% and 35.3%, respectively, compared to a conventional liquid die casting sample.

Reclaiming waste tire rubber by an irradiation technique

Tire rubber recycling reduces production costs, saves resources, and decreases the environmental issues. Waste tire rubber were devulcanized by a laboratory microwave oven with the aid of the devulcanizing agent and the oil. The effect of several devulcanizing agents, hexadecylamine (HDA), Diphenyl disulfide (DPDS), N-cyclohexyl-2-benzothiozyl sulfenamide (CBS) 2-mercaptobenzothiazole disulfide (MBTS) and two types of the oils, aromatic and paraffinic with various contents in different irradiation temperatures was studied. For homogeneous devulcanization, the waste rubber was ground to a median particle size of 319 μm before further treatment and subsequent irradiation process. The results showed that used waste rubber powder was devulcanized effectively. Among of the devulcanizing agents and based on Horikx analysis, formulated compound with DPDS with the sol fraction, crosslink density (CLD) and devulcanization percent of 16.5%, 85 mol/m3 and 48%, respectively, was the most suitable compound for devulcanization when compared with formulated compounds with other devulcanizing agents. Among of compounds with different DPDS content, compound with 30 phr aromatic oil and 6 phr DPDS in formulation with devulcanization temperature of 240 °C, had the best devulcanizing parameters. Paraffinic oil had an adverse effect on devulcanization of the DPDS formulated compounds. For selected studied compounds, during microwave irradiation, a part or total amount of the polysulphides crosslinks were broken and the structure of the remained sulphur crosslinks were mostly mono sulphide. In the morphology study of the most devulcanized compounds, a coarse morphology of the non-devulcanized rubber covered by the devulcanized rubber were observed. The effect of the oil content was also obvious.

Effect of Mn and Fe on the Formation of Fe- and Mn-Rich Intermetallics in Al-5Mg-Mn Alloys Solidified Under Near-Rapid Cooling.

Mn was an important alloying element used in Al–Mg–Mn alloys. However, it had to be limited to a low level (<1.0 wt %) to avoid the formation of coarse intermetallics. In order to take full advantage of the benefits of Mn, research was carried out to investigate the possibility of increasing the content of Mn by studying the effect of cooling rate on the formation of Fe- and Mn-rich intermetallics at different content levels of Mn and Fe. The results indicated that in Al–5Mg–Mn alloy with low Fe content (<0.1 wt %), intermetallic Al6(Fe,Mn) was small in size and amount. With increasing Mn content, intermetallic Al6(Fe,Mn) increased, but in limited amount. In high-Fe-containing Al–5Mg–Mn alloys (0.5 wt % Fe), intermetallic Al6(Fe,Mn) became the dominant phase, even in the alloy with low Mn content (0.39 wt %). Cooling rate played a critical role in the refinement of the intermetallics. Under near-rapid cooling, intermetallic Al6(Fe,Mn) was extremely refined. Even in the high Mn and/or high-Fe-containing alloys, it still demonstrated fine Chinese script structures. However, once the alloy composition passed beyond the eutectic point, the primary intermetallic Al6(Fe,Mn) phase displayed extremely coarse platelet-like morphology. Increasing the content of Fe caused intermetallic Al6(Fe,Mn) to become the primary phase at a lower Mn content.

Mechanical behavior of asphalt mixtures with different aggregate type

Measurement of the effect of aggregate type on mechanical properties of asphalt mixtures is a complex and understudied variable. This paper presents main results of an experimental study about the influence of physical properties of different aggregate type on mechanical behavior of asphalt mixtures. With this purpose, twelve different asphalt mixtures have been manufactured, with the same aggregates distribution, but using three different types of aggregates, obtained by two different shredding processes, and four different types of asphalt bitumen (two with different penetration values, one polymer modified bitumen and one with high modulus). Morphological characterization and surface texture measurement have been carried out according to methodologies proposed by Zingg method and ASTM-D3398 Standard. Additionally, stiffness and cracking resistance of asphalt mixtures have been evaluated at four different temperatures by using stiffness modulus test and Fenix Test, respectively. Main results of this study demonstrate that morphology and surface texture of aggregates, both coarse and fine size, influence on stiffness and cracking resistance of evaluated asphalt mixtures, and that this influence depends on the shredding process and the origin of aggregates.

Facile Fabrication of Lubricant-Infused Wrinkling Surface for Preventing Thrombus Formation and Infection.

Despite the advanced modern biotechniques, thrombosis and bacterial infection of biomedical devices remain common complications that are associated with morbidity and mortality. Most antifouling surfaces are in solid form and cannot simultaneously fulfill the requirements for antithrombosis and antibacterial efficacy. In this work, we present a facile strategy to fabricate a slippery surface. This surface is created by combining photografting polymerization with osmotically driven wrinkling that can generate a coarse morphology, and followed by infusing with fluorocarbon liquid. The lubricant-infused wrinkling slippery surface can greatly prevent protein attachment, reduce platelet adhesion, and suppress thrombus formation in vitro. Furthermore, E. coli and S. aureus attachment on the slippery surfaces is reduced by ∼98.8% and ∼96.9% after 24 h incubation, relative to poly(styrene-b-isobutylene-b-styrene) (SIBS) references. This slippery surface is biocompatible and has no toxicity to L929 cells. This surface-coating strategy that effectively reduces thrombosis and the incidence of infection will greatly decrease healthcare costs.

Electrically tunable pore morphology in nanoporous gold thin films

Nanoporous gold (np-Au) is an emerging nanostructured material that exhibits many desirable properties, including high electrical and thermal conductivity, high surface area-to-volume ratio, tunable pore morphology, well-established surface-binding chemistry, and compatibility with microfabrication. These features make np-Au a popular material for use in fuel cells, optical and electrical biosensors, drug delivery vehicles, neural electrode coatings, and as a model system for nanoscale mechanics. In each of its many applications, np-Au morphology plays an essential role in the overall device operation. Therefore, precise morphological control is necessary to attain optimal device performance. Traditionally, thermal treatment by furnaces and hot plates is used to obtain np-Au with self-similar but coarser morphologies. However, this approach lacks the ability to create different morphologies on a single substrate and requires high temperatures (> 250 °C) incompatible with most plastic substrates. Herein, we report electro-annealing as a novel method that permits control of the extent and location of pore coarsening on a single substrate in one fast treatment step. The electro-annealing entails much lower temperatures (< 150 °C) than traditional thermal treatment, putatively due to electrically assisted phenomena contributing to the thermally activated surface diffusion of gold atoms, responsible for coarsening. Overall, this approach is easily scaled to display multiple pore morphologies on a single chip, therefore enabling high-throughput screening of optimal nanostructures for specific applications.

Microstructural Changes of a Creep-Damaged Nickel-Based K002 Superalloy Containing Hf Element under Different HIP Temperatures

AbstractEffects of hot isostatic pressing (HIP) temperature on the microstructural evolution of a nickel-based K002 superalloy containing Hf element after long-term service were investigated using three different soaking temperatures during HIP. The degraded γ′ precipitates represented coarse and irregular morphology after long-term service. These γ′ precipitates still were of coarse and irregular shape, but the size and volume fraction of γ′ precipitates were markedly reduced under HIP condition of 1,190°C/200 MPa/4 h, indicating that the γ′ precipitates were experiencing a dissolution process. Meanwhile, the concentrically oriented N-type γ′ rafting structure around the cavities was formed. With HIP temperature increase to 1,220°C and 1,250°C, the small-sized, cubic and regular γ′ precipitates were re-precipitated, and the concentrically oriented γ′ structure vanished. The unstable morphology induced by the nucleation and growth of γ matrix was found near the creep cavities, indicating that the solute atoms diffused inward the creep-induced cavities during HIP. However, at HIP temperature of 1,220°C and 1,250°C, a large number of blocky MC(2)-type carbides containing amounts of Hf elements were precipitated, demonstrating that HIP treatment at higher temperatures can result in the formation of a large number of blocky MC(2)-type carbides.

Microstructure and intermediate-temperature mechanical properties of powder metallurgy Ti–6Al–4V alloy prepared by the prealloyed approach

The mechanical properties of powder metallurgy (P/M) Ti–6Al–4V alloys, produced from prealloyed powders by hot isostatic pressing, were evaluated over the intermediate temperature range of 300–500°C. A fully equiaxed or lamellar structure was observed depending on the processing temperature. Microstructural changes were attributed to the beta-transus temperature, predicted as 977°C. As the test temperature increased from 300 to 500°C, the strength of the Ti alloys decreased and their elongation increased, regardless of their initial microstructure. Over the entire temperature range tested, the strength and ductility of equiaxed phase morphologies were higher than those of the lamellar structure. In addition, finer equiaxed structures exhibited higher strength and lower ductility than coarser morphologies. These results were attributed to the initial microstructures of the P/M Ti–6Al–4V alloy samples, as confirmed by evaluating their fracture features.

Study of carbonaceous species, morphology and sources of fine (PM2.5) and coarse (PM10) particles along with their climatic nature in India

The determination of particulate matter (PM2.5 and PM10) is very important due to its impact on climate, visibility reduction and natural environment. In order to identify their nature and relationship with the major synoptic-scale circulation patterns, particles were collected from Pune atmosphere and were analyzed in terms of morphology, carbonaceous species (organic and elemental carbon) and elemental concentration. Average mass concentrations of PM2.5 and PM10 were 104.57±25.70μgm−3 and 169.91±60.75μgm−3, respectively for the entire study period. This indicates that observed values of PM are substantially higher than NAAQS and WHO standards, respectively. The ratio between PM2.5 and PM10 was calculated and varied from 0.51 to 0.78 indicating abundance of fine particles over Pune during the study period. Carbonaceous analysis results showed that concentrations of OC and EC were 31.25 and 2.73μgm−3 for PM2.5 while 33.14 and 2.40μgm−3 for PM10, respectively. The calculated OC/EC ratios were 15.83 and 17.24 for PM2.5 and PM10, respectively indicating abundance of organic carbon which suggests the excess of secondary organic aerosols. The morphological traits such as circularity (<1) and aspect ratio (>1) were determined which indicate that the particles are not perfectly spherical and not elongated in any direction in both size ranges. Effective carbon ratio (ECR) an approach for climate was found to have an average value of 2.42 and 1.74 for PM2.5 and PM10. This clearly indicates that abundance of SOC and lower values of POC and EC could lead to the reduction in atmospheric warming effect due to combustion PM and increases scattering properties of incoming radiations. The monthly air mass backward trajectory cluster analysis was performed which supports the transport of aerosols from the long range transportation as well as the dominance of local sources over SW Indian region. The contribution of local sources was further determined which indicates that motor vehicle is the dominant emitter of carbonaceous aerosols in Pune.

Controlled CaCO3 stearate pre-treatment effects on the interphase adhesion in filled SAN/EPDM blend

Calcium carbonate (CaCO3) fillers pre-treated with the increased amount of stearate were used in order to tune the surface energy for a selective filler migration to the interface in immiscible styrene-acrylonitrile/ethylene–propylene–diene (SAN/EPDM) polymer blends. Various models were used in order to predict the filler accommodation at the blend interface when the interfacial tension becomes low and the wettability is good. The results showed that under optimal thermodynamic conditions, the filler might act as a compatibilizer and significantly improve the blend morphology. The coarse morphology of the initially immiscible SAN/EPDM changed into a fine blend morphology with the addition of the selected CaCO3 fillers with optimal surface energy. Due to the problem with filler agglomeration of initially nanosized CaCO3 fillers, we used masterbatch (MB) compositions for the blend preparation in order to get the better filler distribution. In this paper, the comparison between two types of MB compositions based on SAN and/or EPDM as a surplus phase with the selected filler was made considering the model predictions and its effects on the blend morphology and properties. In the case of using MB(EPDM) in blend preparation, the fine blend morphology resulted in improved mechanical and thermal properties, while with MB(SAN) the coarse blend morphology and worsened properties illustrated the opposite effect.

Effect of Ca addition on modification of primary Mg2Si, hardness and wear behavior in Mg–Si hypereutectic alloys

The effect of Ca addition on modification of primary Mg2Si, hardness and wear behavior in Mg–5 wt.%Si hypereutectic alloy has been investigated. The results showed clearly that without Ca addition, most of primary Mg2Si appeared as coarse dendritic morphology with average size of about 215 μm. With the addition of 0.1 wt.%Ca, the average size of primary Mg2Si decreased to about 98 μm, but their morphologies did not significantly changed. As the addition level of Ca increased to 0.3 wt.%, the average size of primary Mg2Si decreased significantly to about 50 μm and their morphologies changed to polyhedral shape. However, with further increasing Ca addition to 0.6 wt.% and 1 wt.%, some needle-like and blocky CaMgSi particles formed and the average size of primary Mg2Si increased slightly, which could described as over-modification. The present work showed that the optimal modification effect could be obtained when the Ca content in the investigated alloy reached 0.3 wt.%. The modification mechanism may be referred mainly due to poisoning effect resulting from the segregation of Ca atoms at the growth front of the Mg2Si and the adsorption effect of some Ca atoms in the Mg2Si crystal growth plane. The 0.3 wt.%Ca-added alloy has the highest hardness value and the best wear resistance among all other alloys. An excessive Ca addition resulted in the formation of some needle-like and blocky CaMgSi particles, which was detrimental to hardness and wear behavior of the 0.6 wt.% and 1 wt.%Ca-added alloys. The wear mechanism of investigated alloys is a mild abrasive oxidative wear with little adhesion.

Discussion of “On the Refinement Mechanism of Silicon in Al-Si-Cu-Zn Alloy with Addition of Bismuth”*

Despite having been proposed many times, with respect, it is not easy to see the logic underlying this approach. The surface tension of the liquid alloy (a liquid/gas interface) bears no clear relation to the mechanisms of the growth of the silicon phase (on a liquid/solid interface). Nor is it clear that any enhanced ‘wetting’ of the liquid alloy on the Al dendrites occurs, and whether this would in fact aid the formation of silicon. The authors seem unaware that a new theory of ‘modification’ of Si in Al-Si alloys has been proposed which appears to have been completely successful to explain all the features observed so far concerning this complex process. [2] It is based on the fact that during the casting of most alloys, the turbulence of the pouring action entrains the surface oxide on the liquid in the form of fragments of doubled-over oxide films, which have been called bifilms. Al-Si alloys are usually full of a suspension of bifilms. X-ray radiographs reveal snowstorm-like conditions. [3] It seems that silicon nuclei, AlP, precipitate on either side of the bifilms, initiating the growth of Si on the bifilms and straightening them during the lateral growth of the silicon flakes. The unbonded central interface in the bifilm forms the familiar crack often seen down the center of silicon flakes, and minor folds in the bifilm create the often-seen transverse cracks. In this way, the silicon particles appear to be brittle, and their content of cracks, incorporated during their growth, contributes to the impairment of properties. This coarse morphology is the so-called ‘unmodified’ structure.

Effect of P and Sr additions on the microstructure of hypereutectic Al–15Si–14Mg–4Cu alloy

The effects of P and Sr additions on the primary and eutectic phases in Al–15Si–14Mg–4Cu alloy were examined using thermal analysis and microstructural examination. With the addition of P, the primary Mg2Si particles were refined considerably, accompanied by a change in morphology from a coarse dendritic to a fine polygonal shape. Through the addition of Sr, eutectic Mg2Si and Si particle morphologies were also altered from coarse script-like and coarse acicular-type morphologies, respectively, to a fine fibrous form. Iron impurities in the alloy resulted in the formation of the π-Fe phase (Al8Mg3FeSi6) in the structure, and the addition of Sr transformed the morphology of the π-Fe from a script-like to a fine twin platelet form. The results show that addition of Sr or Sr+P reduces the eutectic temperature and reduces the size and therefore increases the number density of Mg2Si particles, Si and π-Fe phases in the alloy.

Effect of Coupling Agent on the Properties of Polymer/Date Pits Composites

The morphology of the fracture surfaces of polymer/date pits composites was investigated. Polymers used in this study were high density polyethylene (HDPE) and polystyrene (PS). Date pits in the form of granules were two types of date pits: khlaas (K) and sekari (S). Two coupling agents, diphenylmethane-4 4′-diisocyanate (DPMI) and ethylene propylene grafted with malice anhydride (EP-g-MA), were used to ease the incorporation of date pit particles into polymer matrix. The SEM micrographs of the neat composites, that is, with no coupling agents, showed coarse morphology with bad dispersion, adhesion, and distribution of date pit particles within the polymer matrix. On the other hand, PS100/K composites coupled with DPMI and EP-g-MA had reasonable dispersed phase size with good distribution and adhesion to the composite matrix which in turn improve the mechanical properties of the resulted polymer/date pits composites.

Sigma phase precipitation on welded SAF 2205 Duplex Stainless Steels after isothermal heat treatment

ABSTRACTDuplex stainless steels are commonly used for various applications owing to their superior corrosion resistance and/or strength. They have ferromagnetic behavior together with a good thermal conductivity and a lower thermal expansion as a result of higher ferrite content than austenitic steels. Their ferrite matrix suffers a decomposition process during aging in the temperature range 650-950° C producing precipitation of austenite, σ and χ, carbides and nitrides. These intermetallic phases are known to be deleterious for corrosion resistance and mechanical properties.In this work the effect of aging time during isothermal treatment at 850°C and 900°C on the microstructure of SAF 2205 Duplex Stainless Steels welded plates has been investigated. The aim of this work is to determine the morphology of σ phase, and perform a quantitative analysis of the precipitation process.Submerged Arc Welding is used for processing. It produces a high content of δ ferrite in the heat affected zone and low content of austenite in the weld. Microstructural examination shows that the σ phase precipitates at δ ferrite/γ interphases. Longer aging treatments give rise to an increase of volume fraction together with a coarser morphology.

Catalytic Wet Peroxide Oxidation of Chlorophenol Over a Ce0.86Cu0.14–x O2 Catalyst

Abstract A Ce0.86Cu0.14–x O2 catalyst was prepared by the citric acid complex method and characterized by X-ray diffraction, scanning electron microscopy, and temperature-programmed reduction, and its activity in the catalytic wet peroxide oxidation of 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) was investigated. The results showed that the Cu2+ ions dissolved into the CeO2 lattice to form a Ce0.86Cu0.14–x O2 solid solution with a coarse, interconnected, porous, and cotton-like morphology. The metal–oxygen bonds were weakened by solid-solution formation in the Ce0.86Cu0.14–x O2 catalyst. This weakening facilitated H2O2 activation and decomposition to form highly oxidative HO∙ species that can lead to significant chlorophenol mineralization. A total organic carbon removal rate greater than 80% was achieved after 2 h reaction at 50°C and at an initial 4-CP and 2,4-DCP concentration of 50 mg/L. The effects of H2O2 dosage, catalyst dosage, and initial chlorophenol concentration on catalytic efficiency were also determined.

Effect of organoclay on blends of individually plasticized thermoplastic starch and polypropylene

Cornstarch and polypropylene (PP) blends were prepared by melt mixing at a constant 70:30 (mass/mass) ratio in a co-rotating twin-screw extruder. Both components were plasticized individually; glycerol and acetyl tributyl citrate (ATBC) were used as plasticizers for starch and PP, respectively. A commercial maleated polypropylene (mPP) was added to the mixtures as a compatibilizing agent. A commercial organoclay was also incorporated at increasing contents (1.0, 2.5 and 5.0mass% over the total mass of the blends). The extruded materials were pelletized, compression-molded, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and capillary rheometry. XRD results indicated that the addition of ATBC contributed to the increase of PP crystallinity from 62% to 72%. The incorporation of the organoclay caused alterations inside the PP-dispersed phase, particularly when its composition reached the amount of 5.0mass%. SEM images revealed a coarse morphology for the blend prepared in the presence of mPP alone. XRD, SEM and DMA data revealed that improvements in the compatibility between the immiscible components were achieved by the organoclay incorporation. The evolution of the XRD patterns for the hybrid materials submitted to aging at high humidity conditions for 120 days indicated that organoclay particles were located preferentially in the starch matrix at the end of this experiment.

Microstructure and mechanical properties of TC21 titanium alloy after heat treatment

Microstructure evolutions during different heat treatments and influence of microstructure on mechanical properties of TC21 titanium alloy were investigated. The results indicate that the excellent mechanical properties can be obtained by adopting air cooling after forging followed by heat treatment of (900 °C, 1 h, AC)+(590 °C, 4 h, AC). Deformation in single β field produces pan-like prior β grains, while annealing in single β field produces equiaxed prior β grains. Cooling rate after forging or annealing in single β field and the subsequent annealing on the top of α+β field determine the content and morphology of coarse α plates. During aging or the third annealing, fine secondary α plates precipitate. Both ultimate strength and yield strength decrease with the content increase of coarse α plates. Decreasing effective slip length and high crack propagation resistance increase the plasticity. The crisscross coarse α plates with large thickness are helpful to enhance the fracture toughness.