Authors: F. Romero, Vicente Amigó, M.D. Salvador, A. Vicente
Abstract: Titanium metal matrix composites were produced. The powder metallurgy route applied
was a conventional route consisting of blending titanium matrix powder with different percentages
of various titanium compounds, as reinforcement particles, followed by cold compaction in a
uniaxial press with a floating matrix and a sintering process in a vacuum furnace. This work studied
the different interactions between the titanium matrix and the various titanium compounds added.
To evaluate these interactions microscopic techniques are used principally, optical and electronic
microscopy, with EDX techniques. By microstructural analysis the reactivity between
reinforcement and matrix particles was investigated, and any new phases that formed during the
sintering process were evaluated. In addition, microhardness test were conducted to study the
mechanical properties associated with the new phases, and to evaluate the relative strength or
weakness of the interfacial zones.
817
Authors: Xian Liang Zhou, Duo Sheng Li, Ai Hua Zou, Xiao Zhen Hua, Zhi Guo Ye, Qing Jun Chen
Abstract: SiCp/Al composites were fabricated by ceramic mold freedom infiltration and pressureless infiltration, respectively. The microstructure and phases are analyzed by metallurgical microscope and coefficient of thermal expansion of SiCp/Al composites were tested by thermal dilatometer. The results show that SiCp/Al composites are compact and uniform. SiC particles were dispersed uniformly in Al matrix, and SiCp segregation was not found in composites. Under a certain SiCp size range, space between SiCp decreases with decreasing of SiCp size, and CTE of SiCp/Al composites also decreases with decreasing of particles size. Compared with CTE of composite with pure aluminum as matrix, CTE of composite with ZL101 as matrix is less. Under the annealing process, CTE of SiCp/Al composites with ZL101 as matrix is less than that with the solution and aging, which indicated that its dimensional stability of resisting to temperature fluctuation is better, and thermal expansion behavior and characteristic of SiCp/Al composites are also better.
658
Authors: Shi Zhong Wei, Liu Jie Xu, Guo Shang Zhang, Ji Wen Li, Bao Zhu Dai
Abstract: Mo-based composites with Al2O3 particles were developed in order to enhance the wear resistance of molybdenum alloys. Using Al2O3 power and pure Mo power as raw materials, the Molybdenum powders mixed with Al2O3 particles were prepared using planetary ball mill. And then the Mo-based composites with 3-10vol.% Alumina were prepared by compaction and sintering at 1840°C. The morphology of the Molybdenum powder and microstructure of the composites were analyzed by SEM and XRD. The micro-hardness, density and wear property of composites were researched. The results show that the microstructure of composites is composed of α-Al2O3 particles and Molybdenum matrix. With the increase of Alumina content, the microhardness of Molybdenum matrix increases, and the density first increases and then decreases. The friction coefficient of composite is scarcely affected by the alumina content. While the wear resistance of the composites rises with the increase of Alumina content. The wear failure is caused by abrasive wear characterized by obvious plow furrow and abrasive dust on the worn surface.
467
Authors: Zhu Rui, Yu Tao Zhao, Song Li Zhang, Zhi Hong Jia
Abstract: Abstract:Aluminum matrx composites reinforced by in situ ZrB2 particles are fabricated from A356-AlB-K2ZrF6 system via in-situ melt reaction method, and the morphologies, sizes and distributions of the in situ particles as well as the microstructures, mechanical mechanisms of the composites are investigated by XRD,SEM,TEM and tensile tests. The results indicate that the morphologies of the in situ particles are mainly with ball-shape, the sizes are in nanometer scale and the distributions in the matrix are uniform. The interfaces between the in situ particles and the aluminum matrix are net and no interfacial outgrowth is observed.
122
Authors: Dong Chen, Zhe Chen, Peng Zhang, Yi Jie Zhang, Haiheng Ma, Hao Wei Wang
Abstract: In-situ TiB2 particles reinforced AA7055 composites were fabricated through mixed-salts route and their bending properties were studied. The composites reinforced with 5 wt % and 10 wt% TiB2 exhibit higher bending strength than the unreinforced matrix alloy. The improvement in bending strength may be attributed to dislocation strengthening, Orowan strengthening, and grain strengthening. The good bonding between the reinforcements and the matrix also plays an important role.
1005