Melt Infiltration Casting of Alumina Silicon Carbide and Boron Carbide Reinforced Aluminum Matrix Composites

Abstract

This paper discuss the effect of processing details such as particle size, sintering temperature, preform preparation, aluminum alloy characteristics and melt temperature on the final mechanical properties of ceramic phase reinforced metal matrix composites. Since alloy composition was determined as 7075 and 7085 optimum solutionizing and ageing temperatures were studied to determine maximum hardness values. For only 7085 alloy best solutionizing temperature is 465°C and for 7075 alloy the maximum hardness achived as 178 BHN after heat treatment at 475°C. Alloys were heat treated for recystallization after hot rolling grain size were measured as 100-120 µm for 7085 alloy matrix.Various sintering temperatures were used for preform preparation such as 1300-1450°C. In 85% Al 2 O 3 reinforced 7085 Alloy based MMCs preforms sintered at 1450°C high hardness values were achieved as 545 BHN. Intermetallic phase was determined in 7075 and 7085 alloys selected as alloy matrix. Al 2 Cu intermetallic pecipitate (θ phase) was determined as dominant second phase after T6 heat treatment but highly expected phase in 7000 series alloys MgZn 2 (η phase) was not determined by XRD and SEM analysis techniques due to ultrafine precipitate size and homogeneous distribution.

Improving thermal conductivity of AlSiC composites by post-oxidization of reaction-bonded silicon carbide preforms

“…This is due to the fact that SiC becomes thermodynamically unstable at temperatures above the melting point of aluminum [27][28][29] . As described in the previous report 9,27,30,31 , the threshold values for carbon activity required for the generation of Al Another factor of the Al 4 C 3 generation is the relatively long in ltration period 31,32 . Vacuum pressure in ltration is a well-known procedure for in ltrating molten aluminum into porous preforms to obtain AlSiC composites [32][33][34] .…”

A study of the structure and properties of material based on an iron – copper composite powder

“…There is a technology for rolling metal powders, which produces dense billets [6], but the disadvantage of this technology is the impossibility of manufacturing products of complex shape. It is known from [7] that porous frames can be saturated with low-melting metals. However, this technology is sufficiently energy intensive and requires special equipment, which also limits its use in the manufacturing practice of powder metallurgy.…”

COMPARATIVE MECHANICAL PROPERTIES STUDIES ON HEAT & UNHEAT TREATED AL7075 ALLOY HYBRID COMPOSITES (IN PRESS)

“…Optimization and control of various parameters during the process of manufacturing will enhance the ability to disperse the particles evenly. Kalkanli et al, [12] compared the enhancement in the flexural and tensile strength of the aluminum composite with and without heat treatment. The adding of SiC to the aluminum increased in above mentioned properties.…”