Journal of Modern Physics, 2013, 4, 331-336 http://dx.doi.org/10.4236/jmp.2013.43045 Published Online March 2013 (http://www.scirp.org/journal/jmp) Temperature Dependence of Density and Thermal Expansion of Wrought Aluminum Alloys 7041, 7075 and 7095 by Gamma Ray Attenuation Method Kethireddy Narender 1 , Ammiraju Sowbhagya Madhusudhan Rao 2 , Kalvala Gopal Kishan Rao 3 , Nallacheruvu Gopi Krishna 1 1 Department of Physics, Kakatiya University, Warangal, India 2 Varadha Reddy College of Engineering, Warangal, India 3 CIC, Kakatiya University, Warangal, India Email: ngopikrishna2012@yahoo.com Received December 22, 2012; revised January 25, 2013; accepted February 4, 2013 ABSTRACT The gamma quanta attenuation studies have been carried out to determine mass attenuation coefficients of 7041, 7075 and 7095 wrought aluminum alloys. The temperature dependence of linear attenuation coefficient, density and thermal expansion of these wrought aluminum alloys in the temperature range 300 K - 850 K have been reported. The meas- urements were done by using a gamma ray densitometer designed and fabricated in our laboratory. The data on varia- tion of density and linear thermal expansion with temperature have been represented by linear equations. Volume ther- mal expansion coefficients have been reported. Keywords: Density; Thermal Expansion; Linear Attenuation Coefficient; Mass Attenuation Coefficient 1. Introduction Number of methods [1-13] have evolved for the determi- nation of density and thermal expansion of solids at high temperature like Archimedean method, pycnometry, dila- tometry, electromagnetic levitation, Method of maximal pressure in a gas bubble, method of sessile drop, hydro- static weighing, high temperature electrostatic levitation and gamma ray densitometry. Thermal expansion studies on isotropic solids have been reported by several workers using X-ray diffraction [1,2], dilatometry [3,4], Fabrey- Perot interference method [6] and by other theoretical models [6-13]. Density and Thermal expansion are fun- damental thermo physical properties of solids. The study of temperature dependence of these properties is very im- portant in understanding the temperature variation of other properties like elastic constants, refractive indices, dielectric constants, thermal conductivity, diffusion coef- ficients and other heat transfer dimensionless numbers. Thermal expansion of solids is of technical importance as it determines the thermal stability and thermal shock re- sistance of the material. In general the thermal expansion characteristics decide the choice of material for the con- struction of metrological instruments and in the choice of container material in nuclear fuel technology. Aluminum alloys are very important and extremely useful engineering materials with very good physical properties and finds many applications in modern tech- nology. 7041, 7075 and 7095 aluminum alloys have wide range of applications in aerospace, military and nuclear industry. The gamma radiation attenuation technique for the determination of thermo physical properties in the condensed state offers several advantages over other me- thods at high temperatures. This is possible because the gamma ray is not in any kind of physical or thermal con- tact with the material and hence the thermal losses are also reduced and this condition eliminates sample and probe compatibility problem. Using this technique Drot- ning [14] measured thermal expansion of isotropic solid materials at high temperatures. He studied thermal ex- pansion of Aluminum and type 303 stainless steel at high temperatures and such studies have been extended by him to study the thermal expansion of metals and glasses in the condensed state [14,15]. Recently the gamma ra- diation attenuation technique has been used to measure the temperature dependence of density of metals [16-19], alloys [20-27] at high temperatures. It is desirable to study the thermophysical properties of new materials at high temperatures for their use in practical applications. There is no study on the temperature variation of thermo physical properties of 7041, 7075 and 7095 aluminum alloys and as such, in the present article, we report the Copyright © 2013 SciRes. JMP