J. Bi

Property-microstructure correlation in in situ formed Al2O3, TiB2 and Al3Ti mixture-reinforced aluminium composites

The in situ formed Al2O3, TiB2 and Al3Ti mixture-reinforced aluminium composites were successfully fabricated by the reaction sintering of the TiO2-B-Al system in a vacuum. With increasing boron content in the TiO2-B-Al system, the amount of generated TiB2 in the composites increased and Al3Ti content decreased. At the same time the distribution uniformity of the in situ formed Al2O3 and TiB2 particulates was obviously improved, and the size of the Al3Ti particles was reduced. The in situ Al2O3 and TiB2 particulates had sizes from 0.096–1.88 μm. The interface between the in situ formed particulates and the aluminium matrix was clean, and no consistent crystallographic orientation relationship was found. The strength and elastic modulus of the composites was significantly improved by lowering the Al3Ti content. When the boron content in the TiO2-B-Al system rose, the morphology of the tensile fracture surface of the composites was changed from large fractured Al3Ti blocks and fine dimples, to fine dimples and pulled-out particulates. The strengthening and fracture of the composites have been modelled.

CREEP-BEHAVIOR OF TIC-PARTICULATE-REINFORCED TI ALLOY COMPOSITE

Creep behavior of the TiC-particulate-reinforced Ti alloy composite has been investigated at temperatures from 500 to 650-degrees-C and stresses from 230 to 430 MPa. Creep strain rates of the composite are lower than those of the matrix alloy by one order of magnitude. The lower creep rates for the composite can be attributed to Youngs modulus effect. Creep fracture of the composite is produced by the cavitation at the interfaces of TiC and matrix and the cleavage of TiC. There are dimples on the fracture surface of the matrix which are similar to those of the matrix alloy.

IN-SITU AL4C3 DISPERSOID AND SIC PARTICLE MIXTURE-REINFORCED ALUMINUM COMPOSITE

If in-situ ultrafine particles are introduced into ceramic particles or whiskers reinforced aluminum matrix composites to dispersively strengthen composite matrix, the elevated temperature strength of these composites would be raised because the in-situ formed dispersoids are thermally stable and assure that the composite matrix has enough strength to transfer stress. Stiff ultrafine (<1[mu]m) ceramic particles, including TiB[sub 2], TiC and Al[sub 4]C[sub 3], have been formed in-situ by an exothermal process termed XD[trademark] technology. The in-situ composites exhibit improved strength retention at elevated temperatures, and useful increases in wear and fatigue resistance. The aim of the present investigation was to form in-situ Al[sub 4]C[sub 3] dispersoid in SiCp/Al composite to improve the elevated temperature strength of the composite through strengthening the aluminum matrix by the Al[sub 4]C[sub 3] dispersoid. Such an investigation has not been reported in the literature.

Aluminium borate whisker reinforced Al-8.5 Fe-1.3 V-1.7 Si composite

changsha inst technol,changsha 410073,peoples r china.;ma, zy (reprint author), chinese acad sci,inst met res,atom imaging solids lab,shenyang 110015,peoples r china

Effect of interlayer on properties of diffusion bonded joints of silicon carbide particulate-reinforced aluminum composites

chinese acad sci, inst met res, shenyang 110015, peoples r china.;zhao, mj (reprint author), chinese acad sci, inst met res, shenyang 110015, peoples r china

Creep deformation behavior of SiC particulate-reinforced Al–C–O composite

Creep behaviour of 10 vol% SiC particulate-reinforced Al–C–O– composite has been investigated at the temperatures of 623 and 723 K. The addition of SiC particulates in Al–C–O alloy decreases creep rates by two to four orders of magnitude, compared with Al–C–O matrix alloy. The stress and temperature dependences of creep rates of the composite are similar to those of the Al–C–O matrix alloy. The threshold stress for creep was used to analyse the experimental data of the composite. The creep rates of the composite are concluded to be controlled by lattice diffusion of aluminium.

Microstructure and properties of TiC/NiCr cermets produced by partial liquid-phase sintering

chinese acad sci, inst met res, shenyang 110015, peoples r china.;liu, y (reprint author), chinese acad sci, inst met res, shenyang 110015, peoples r china

Mechanical properties of L1(2) structure intermetallics produced from elemental powder mixtures

chinese acad sci, inst met res, state key lab rsa, shenyang 110015, peoples r china. chinese acad sci, inst met res, shenyang 110015, peoples r china.;wang, zb (reprint author), chinese acad sci, inst met res, state key lab rsa, shenyang 110015, peoples r china