Meihui Songy Gaohui Wu Wenshu Yang Wei Jia Ziyang Xiu Guoqin Chen
材料科学技术（英）
The carbon fibers and the woven reinforced magnesium matrix composites were fabricated by pressure infiltration method. Effects of fiber species, fiber arrangement, hybrid particles and environment temperature on microstructures and properties of the composite were studied. Results showed that the mechanical properties at ambient temperature were affected by interfacial reaction. The magnesium matrix composites reinforced with graphite fibers showed higher strength and elastic modulus due to less interfacial reaction. During load-ing, the fibers were pulled out and the load was transferred through the interfaces, then the fiber bundles were fractured, finally the whole specimen failed. The introduction of hybrid SiC particles during fabrication can improve the mechanical properties of the magnesium matrix composites. Moreover, taking orthogonal carbon fiber woven as reinforcement can modify the anisotropy and reliability of materials.
关键词:
Magnesium matrix composites
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Mechanical property
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Interfacial reaction
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Pressure infiltration
Hui Wang Donghui Yang Siyuan He Deping He
材料科学技术（英）
The open-cell Al foam core sandwiches (AFCSs) were successfully fabricated by using a specially designed Zn-Al-Cu based filler alloy via vibration aided liquid phase bonding method. The effects of the vibration on the bonding seam were investigated and the bonding strength between Al foam core and solid Al alloy face sheet was tested by shearing tests. The results show that vibration can significantly improve the quality of the bonding and the shearing strength of the bonding seam, which implies that this joining method has a good potential in practical applications.
关键词:
Open-cell Al foam core sandwich
,
Liquid phase bonding
,
Vibration
,
Fabrication
,
Mechanical property
Hui Wang Donghui Yang Siyuan He Deping He
材料科学技术（英）
The open-cell Al foam core sandwiches (AFCSs) were successfully fabricated by using a specially designed Zn-Al-Cu based filler alloy via vibration aided liquid phase bonding method. The effects of the vibration on the bonding seam were investigated and the bonding strength between Al foam core and solid Al alloy face sheet was tested by shearing tests. The results show that vibration can significantly improve the quality of the bonding and the shearing strength of the bonding seam, which implies that this joining method has a good potential in practical applications.
关键词:
Open-cell Al foam core sandwich
,
Liquid phase bonding
,
Vibration
,
Fabrication
,
Mechanical property
Weiguo Jiang
材料科学技术（英）
A novel water-soluble core material composed of polyethylene glycol, sodium chloride, mica powder and plasticizer was prepared. The compressive strength, bend strength, hygroscopic coefficient and the material solubility in water were investigated. The results show that the compressive yield strength of the soluble core can reach 1 MPa and the highest compressive strength can reach 4 MPa, the bend strength is as high as 6.65 MPa, the hygroscopic coefficient is lower than 0.22%/month and the solubility of suitable core material is 35.7-55.75 g/(min·m2). The wax pattern with undercuts was prepared successfully by using the novel water-soluble core material.
关键词:
Investment cast
,
Core materials
,
Mechanical property
,
Microstructure
Xiangwen Zhou Yuefeng Zhu Ji Liang Suyuan Yu
材料科学技术（英）
A novel technology to prepare styrene-butadiene rubber (SBR)/carbon nanotubes (CNTs) composites was developed by combining a spray drying method and a subsequent mechanical mixing process. The cross-linking degrees of the vulcanized composites increased gradually with the additive CNTs contents. By comparing with those of the pure SBR composites, the mechanical properties such as tensile strength, tear strength and hardness of the composites filled with CNTs at certain contents were dramatically improved almost by 600%, 250% and 70%, respectively. The fabrication of the CNTs filled with SBR composites by combination of the spray drying method and subsequent mechanical mixing process was effective for enhancing the reinforcement
effects of CNTs in rubbers. The novel technology can also open a new route for the modification and reinforcement on the nanocomposites with large amount of CNTs.
关键词:
Carbon nanotubes
,
styrene-butadiene rubber
,
spray drying
,
mechanical mixing
,
nanocomposite
,
mechanical property
G.M. Xie
材料科学技术（英）
Friction stir welding (FSW) of Mg{Zn{Y{Zr plates with 6 mm in thickness was successfully carried out under a wide range of rotation rates of 600{1200 r/min with a constant traverse speed of 100 mm/min. After FSW, the coarse grains in the parent material (PM) were changed into fine equiaxed recrystallized grains at the nugget zone (NZ). Furthermore, the coarse Mg-Zn-Y particles (W-phase) were broken up and dispersed homogenously into the Mg matrix. With increasing rotation rates, the size of the W-phase particles at the NZ significantly decreased, but the recrystallized grain size tended to increase. The hardness values of the NZs for all the FSW joints were higher than those of the PM, and the lowest hardness values were detected in the heat affected zone (HAZ). The fracture occurred in the thermo-mechanical affected zone (TMAZ) on the advancing side for all the FSW joints in the tensile test, due to the incompatibility of the plastic deformation between the NZ and TMAZ caused by remarkably different orientation of grains and W-phase particles. The strength of FSW joint reaches 90% of that of its PM.
关键词:
Friction stir welding
,
null
,
null
,
null
王晨
,
李媛
,
王国材
,
陈武山
,
Hadjipanayis G C
材料热处理学报
研究了Ce69.5-xCu18Al11Nb1.5Yx(x=0,1,2,3)块体非晶的非晶形成能力、力学性能和耐腐蚀性能.结果表明:添加Y元素能够有效提高Ce-Cu-Al-Nb合金的非晶形成能力.其中,Ce675Cu18Al11Nb1.5Y2样品具有最佳的非晶形成能力,过冷液相区△Tx=97 K,玻璃化转变温度Tg=349 K.在298 K进行压缩时,所有样品都表现出脆性断裂行为,断口形貌为典型的叶脉状花样.在363 K进行压缩时,所有样品都表现出明显的宏观塑性变形行为,当x=0～2时,可以观察到应力过冲现象.Ce67.5Cu18Al11Nb1.5Y2样品在塑性变形时,其流变应力最低,应变平台区最宽,有利于塑性加工.同时发现,添加Y可以改善Ce-Cu-Al-Nb合金的耐腐蚀性能,其中Ce67.5 Cu18Al11Nb1.5Y2样品的耐腐蚀性能最佳.
关键词:
块体非晶
,
Ce基合金
,
力学性能
,
腐蚀
Na Peng
材料科学技术（英）
Two near α titanium alloys Ti-5.6Al-4.8Sn-2.0Zr-1Mo-0.35Si (1#) and Ti-6.0Al-4.8Sn-2.0Zr-1Mo-0.35Si (2#) were solution-treated in the upper α+β phase fields and the duplex mixture microstructures consisting of the less volume fraction primary phase ( αp) and the transformed phase (βt) were obtained. The aging treatments were carried out at 700℃ for 1# alloy and 760℃ for 2# alloy under varied terms, respectively. It guaranteed 2 ordered phase to precipitate only in p but not in t for the two alloys. The slower precipitation and growth of the α2 ordered phase and silicide was observed in 1# alloy in comparison with that in 2# alloy. The mechanical properties including tensile strength and ductility, the creep and lasting properties at the temperature of 600℃ were investigated. Prolonging aging time did not predominantly change the tensile strength and ductility for the two alloys. The 600℃/100h thermal exposure caused a notable decrease of tensile ductility in 2# alloy though no distinct decrease could be observed in 1# alloy after the thermal exposure. The lasting property of 1# alloy was increased with prolonging aging time and finally equal to or even better than that of 2# alloy. Nevertheless, No evident increase emerged in 2# alloy with prolonging aging time. Similarly, the creep property of 1 # alloy monotonously increased with increasing aging time and finally equal to or even better than that of 2# alloy. No evident increase could be observed for 2# alloy. It can be deduced that the overgrowth of α2 ordered phase and silicide is unable to enhance hot strength properties but causes an unacceptable damage to tensile ductility. The optimum equilibrium of the comprehensive properties depending on the proper control of α2 ordered phase and silicide can be achieved by selecting aging temperature and time.
关键词:
Titanium alloy
,
null
,
null
