共查询到18条相似文献,搜索用时 140 毫秒
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通过金相、扫描电镜观察、能谱分析和力学性能检测,研究了加入Ce后202不锈钢的强度、塑性、冲击韧性变化。在相同的热处理工艺条件下,分别加入不同含量的Ce,与不添加Ce的202不锈钢的力学性能进行比较。结果表明:钢中加入Ce可改变夹杂物形态,并且在适当的范围内可显著提高202不锈钢的强度、塑性、横向冲击韧性。当Ce的质量分数为0.016%时,202不锈钢可获得最佳的综合力学性能。 相似文献
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基于现有低碳钢焊条性能的特点,针对典型低碳钢焊条(E4303型焊条)抗裂性较差的问题,在新型低碳钢焊条药皮配方开发研制中采取药皮过渡微量的镧钇元素.通过冲击韧性、拉伸、硬度、金相等试验研究镧钇元素对低碳钢焊条熔敷金属组织和力学性能的影响,利用扫描电子显微镜对显微组织进行观察分析,用X射线荧光光谱仪进行光谱分析.结果表明:加入适量的镧钇元素能够细化熔敷金属显微组织,提高熔敷金属的冲击韧性.当镧钇元素加入量最佳(3.5%镧和0.6%钇)时,熔敷金属的冲击韧性提高了38.8%,延伸率提高了25%,抗拉强度提高了11.9%,屈服强度提高了10.9%,硬度却不下降. 相似文献
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铈及其碳化物对钢力学性能的影响 总被引:3,自引:2,他引:1
通过金相、扫描电镜能谱分析和冲击、拉伸等实验方法,研究了钢中及其碳化强度、塑性、冲击韧度等力学性能的影响,固溶于钢中的微量有抑制奥氏体晶粒粗的作用,至少可使奥氏体晶粒粗化温度提高50K以上;如果铈在晶界上过量富集,可显著降低钢的冲击韧度。钢中的碳化物对钢的韧性和塑性都有改善作用,对钢的屈服点没有发现显著的影响。 相似文献
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《中国稀土学报》2021,(4)
工业化试验冶炼不同稀土含量的HRB500E抗震钢筋,采用光学显微镜(OM),扫描电镜(SEM)和能谱仪(EDS)等手段研究稀土对HRB500E抗震钢筋夹杂物、显微组织和力学性能的影响,并探究稀土对夹杂物变质和低温冲击韧性的作用机制。结果表明:添加0.0066%稀土可以有效降低钢中的S含量,钢中单独的长条状的MnS和大尺寸不规则形状的Al-Mn-O夹杂物消失,变质为小尺寸球状的REAlO_3-MnS的复合夹杂物。抗震钢筋的显微组织细化,在保证拉伸性能的基础上,低温冲击韧性显著提升,-40℃冲击功由7.55 J提升至10.7 J,-60℃冲击功由5.60 J升至8.00 J,分别提高41.72%, 42.86%。 相似文献
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Shuiping Li 《先进技术聚合物》2020,31(4):722-730
The improvement of mechanical properties and toughness of nanoparticles for epoxy composites was mostly dependent on the disperse state of nanoparticles in epoxy matrices. When the content of nanoparticles was higher than a threshold value, it was easy to aggregate and then affect the improvement effect. Pickering emulsion was prepared using SiO2 nanoparticles as emulsifier and functional monomer as oil phase. The influence of Pickering emulsion on the curing process was investigated. The effect of Pickering emulsion on the mechanical properties, toughness, and glass transition temperature (Tg) was studied. Impact and tensile fracture surface were observed by scanning electron microscopy (SEM). Results from differential scanning calorimeter (DSC), tensile, impact, and fracture toughness tests are provided. The results indicated that the introduction of Pickering emulsion can eliminate the residual stress and accelerate curing reaction. Epoxy composites were capable of increasing tensile strength by up to 29.9%, impact strength of three‐fold, fracture toughness of 35%, and Tg of 20.7°C in comparison with the reference sample. SEM images showed that SiO2 nanoparticles exhibit a good dispersion in epoxy matrix. The increases in mechanical properties, toughness, and Tg of epoxy composites were attributed to the “Second Phase Toughness” mechanism. 相似文献
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利用数字化冲击试验装置和微观分析手段,研究了La,Ce对低硫氧合金结构钢冲击性能的影响,并对影响机制进行了分析。结果表明,稀土元素有改善低硫氧合金结构钢冲击韧性的作用,适宜的稀土含量大约为0.005%。稀土元素通过净化晶界和变质夹杂物,将提高晶界的强度,减少裂纹通过缺陷的贯通而扩展的可能,从而使材料承受冲击载荷时可以吸收更多的裂纹扩展的能量。稀土过量时,将弱化晶界,形成脆硬的磷化物、铁-稀土金属间化合物等,弱化材料的冲击性能。 相似文献
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This paper reports the improvement of the mechanical properties of epoxy/nanoclay/multi-walled carbon nanotube (MWNT) nanocomposites prepared by the solution casting method for a range of pre-cure temperatures (room temperature, 50, and 70 °C), cure temperature (120, 130, and 140 °C), nanoclay content (0.5, 1.0, 1.5 wt%) and content of MWNT (0.2, 0.6, 1.0 wt%) for three levels. The influence of these parameters on the mechanical properties of epoxy/nanoclay/MWNT has been investigated using Taguchi's experimental design. The output measured responses are the tensile properties (tensile modulus, tensile strength and strain at break), impact strength and fracture toughness. From the Analysis of Mean (ANOM) and Analysis of Variance (ANOVA), MWNT content, pre-cure temperature and cure temperature had the most significant effects for the impact strength with contribution percentages of 38%, 28% and 23% respectively. However, for the fracture toughness and strain at break, the enhancements of properties come from the nanoclay content (59%), MWNT content (18%) and pre-cure temperature (23%). While the improvement in tensile strength was influenced by nanoclay and MWNT content, the cure temperature has a stronger effect on the tensile modulus. In this respect, Taguchi method points to the Taguchi method, in this way, points to the dominant parameters and gives the optimum parameter settings for each mechanical property. Confirmation experiments were performed with the optimum parameter settings and the mechanical properties were measured compared with the predicted results. 相似文献
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稀土对MoSi2力学性能和抗氧化性能的影响 总被引:2,自引:0,他引:2
采用自蔓延和真空烧结方法制备了掺杂0.9%La2O3的MoSi2基复合材料,利用热重分析法,SEM和X射线考察了La2O3颗粒对MoSi2力学性能、抗氧化特性以及循环氧化后力学性能的影响。结果表明,与纯MoSi2相比,RE/MoSi2材料的弯曲强度和断裂韧性分别提高了46%和78%;稀土对MoSi2材料的强韧化机制主要是细晶强化、弥散强化和细晶韧化。RE/MoSi2的氧化增重是纯MoSi2的2.5倍,稀土使MoSiz材料的抗氧化性能降低。由于纯MoSi2材料氧化后的晶粒长大,其抗弯强度比氧化前降低了17%。稀土对MoSi2氧化时的晶粒长大倾向有抑制作用,使得RE/MoSi2材料的抗弯强度基本不变。 相似文献
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Chao Ying Wan Yong Zhang Yin Xi Zhang Xiu Ying Qiao Guo Min Teng 《Journal of Polymer Science.Polymer Physics》2004,42(2):286-295
Toughening‐modified poly(vinyl chloride) (PVC)/organophilic montmorillonite (OMMT) composites with an impact‐modifier resin (Blendex 338) were prepared by melt intercalation, and their microstructures were investigated with wide‐angle X‐ray diffraction, transmission electron microscopy, and scanning electron microscopy. The mechanical properties of the PVC composites were examined in terms of the content of Blendex and OMMT, and the fracture toughness was analyzed with a modified essential work of fracture model. Intercalated structures were found in the PVC/OMMT composites with or without Blendex. Either Blendex or OMMT could improve the elongation at break and notched impact strength of PVC at proper contents. With the addition of 30 phr or more of Blendex, supertough behavior was observed for PVC/Blendex blends, and their notched impact strength was increased more than 3319% compared with that of pristine PVC. Furthermore, the addition of OMMT greatly improved both the toughness and strength of PVC/Blendex blends, and the toughening effect of OMMT on PVC/Blendex blends was much larger than that on pristine PVC. Blendex and OMMT synergistically improved the mechanical properties of PVC. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 286–295, 2004 相似文献
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Azman Hassan Norhayani Othman Mat Uzir Wahit Lim Jian Wei Abdul Razak Rahmat Zainal Ariffin Mohd Ishak 《Macromolecular Symposia》2006,239(1):182-191
A series of polyamide 6/polypropylene (PA6/PP) blends and nanocomposites containing 4 wt% of organophilic modified montmorillonite (MMT) were designed and prepared by melt compounding followed by injection molding. Maleic anhydride polyethylene octene elastomer (POEgMAH) was used as impact modifier as well as compatibilizer in the blend system. Three weight ratios of PA6/PP blends were prepared i.e. 80:20, 70:30, and 60:40. The mechanical properties of PA6/PP blends and nanocomposite were studied through flexural and impact properties. Scanning electron microscopy (SEM) was used to study the microstructure. The incorporation of 10 wt% POEgMAH into PA6/PP blends significantly increased the toughness with a corresponding reduction in strength and stiffness. However, on further addition of 4 wt% organoclay, the strength and modulus increased but with a sacrifice in impact strength. It was also found that the mechanical properties are a function of blend ratio with 70:30 PA6/PP having the highest impact strength, both for blends and nanocomposites. The morphological study revealed that within the blend ratio studied, the higher the PA6 content, the finer were the POEgMAH particles. 相似文献
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WANGWei-zhi WUQiang-hua QUBao-jun 《高等学校化学研究》2004,20(1):111-113
The mechanical properties and the crystal morphological structures of the dynamically photocrosslinked polypropylene (PP)/ethylene-propylene-diene terpolymer (EPDM) blends have been studied by means of mechanical tests, wide-angle X-ray diffraction(WAXD), and differential scanning calorimetry(DSC). The dynamically photocrosslinking of the PP/EPDM blends can improve the mechanical properties considerably, especially the notched Izod impact strength at low temperatures. The data obtained from the mechanical tests show that the notched Izod impact strength of the dynamically photocrosslinked sample with 30% EPDM at -20℃ is about six times that of the uncrosslinked sample with the same EPDM component. The results from the gel content, the results of WAXD, and the DSC measurements reveal the enhanced mechanism of the impact strength for the dynamically photocrosslinked PP/EPDM blends as follows: (1) There exists the crosslinking of the EPDM phase in the photocrosslinked PP/EPDM blends ; (2) The β-type crystal structureof PP is formed and the content of α-type crystal decreases with increasing the EPDM component; (3) The graft copolymer of PP-g-EPDM is formed at the interface between the PP and EPDM components. All the above changes of the crystal morphological structures are favorable for increasing the compatibility and enhancing the toughness of the PP/EPDM blends at low temperatures. 相似文献