Meihui Songy Gaohui Wu Wenshu Yang Wei Jia Ziyang Xiu Guoqin Chen
材料科学技术（英文）
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
Ning Zhao
材料科学技术（英文）
The wetting property of (Sn-9Zn)-2Cu (wt pct) on Ni substrate and the evolution of interfacial microstructure in (Sn-9Zn)-2Cu/Ni joints during soldering as well as isothermal aging were studied. The wetting ability of eutectic Sn-9Zn solder on Ni substrate was markedly improved by adding 2 wt pct Cu into this solder alloy. Plate-like Cu5Zn8 intermetallic compounds (IMCs) were detected in (Sn-9Zn)-2Cu solder matrix. A continuous Ni5Zn21 IMC layer was formed at (Sn-9Zn)-2Cu/Ni interface after soldering. This IMC layer kept its type and integrality even after aging at 170°C for up to 1000 h. At the early aging stage (before 500 h), the IMC layer grew fast and its thickness followed a linear relationship with the square root of aging time. Thereafter, however, the thickness increased very slowly with longer aging time. When the joints were aged for 1000 h,
a new IMC phase, (Cu,Ni)5Zn8, was found in the matrix near the interface. The formation of (Cu,Ni)5Zn8 phase can be attributed to the di®usion of Ni atoms into the solder matrix from the substrate.
关键词:
Lead-free solder
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null
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null
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null
Qiulian Zeng
材料科学技术（英文）
Sn-10Sb-5Cu lead-free solder was fabricated for high temperature application in electronic package. Wetting behaviors and interfacial reaction between such a high temperature lead-free solder and Cu substrate were investigated and compared with those of 95Pb-Sn solder. The results showed that the wetting properties of Sn-10Sb-5Cu solder are superior to those of 95Pb-Sn solder in maximum wetting force, wetting time and wetting angle in the temperature range of 340{400°C. However, the surface of the Sn-10Sb-5Cu solder sample after wetting balance tests was rougher than that of 95Pb-Sn solder at the temperature lower than 360°C. In static liquid-state interfacial reaction, the types and thickness of the intermetallic compounds (IMCs) of both solders were different from each other. The wetting kinetics in the Sn-10Sb-5Cu/Cu system was more rapid than that in 95Pb-Sn /Cu system, and the higher formation rate of IMCs in the former system was considered as the reason.
关键词:
Wetting
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null
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null
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