Author : Ahmed Rajih Hassan

Machinable glass – ceramic material have a good chemical properties, the optical properties , as well as mechanical and thermal properties, that allow glass – ceramic material to be used as main component in aerospace application ( shuttle), bio-material for the veneering of metal restoration in destroy. In this work prepare glass-ceramic from raw material Oxides + BaO ) , then obtain density , Young modulus and Hardness. After that studies effect of Lithium and Beryllium additions in properties of glass ceramic. You can see that the porosity decrease with increase of %Wt Li to reach 4% and %wt Be to reach 5%.Li addition leads to decrease density of glass-Ceramic to ( 1.89*103Kg/m3 when add 9% Li ), also Be addition decrease density of glass-Ceramic to ( 2.06*103 Kg/m3 when add 9%Be), this result prefer in application of glass-Ceramic, especially in aerospace application ( window of shuttle ). The addition of 9% Li lead to increase young modulus ( E ) to ( 73.5 Gpa ) also addition of 9% Be lead to increase ( E ) to ( 69 Gpa ) and the addition of ( 5% ) of Li and ( 5% ) of Be together increase young modulus to ( 78 Gpa ). Lithium addition on glass-Ceramic leads to decrease Hardness to (259 HB at 9% Li ), but Beryllium addition lead to increase Hardness to ( 312 HB ), and addition of Li and Be together (5%Be + 5% Li )lead to increase Hardness to (289 HB ). Impact energy was found to increase with increase in Li and Be addition to reach (25.1 Nm ) and (27.1 Nm ) when add (9%) of Be and Li respectively. In microstructure test the addition of Be and Li metal through the specimens leading to a consolidate for all the alternative properties. See the diffusion process occurred of Li as base metal in glass-Ceramic and precipitation of Be as a second phase in glass-Ceramic.

Keyword: Glass-ceramic , composite materials, Lithium, Beryllium, mechanical properties, physical properties.

Article published in International Journal of Current  Engineering  and Technology, Vol.3,No.5(Dec- 2013)