Anelastic Behavior of Small Dimensioned Aluminum

Abstract

In the present research, results are presented regarding the anelasticity of 99.999% pure aluminum thin films, either deposited on silica substrates or as free-standing sheets obtained by cold rolling. Mechanical Spectroscopy (MS) tests, namely measurements of dynamic modulus and damping vs. temperature, were performed using a vibrating reed analyzer under vacuum. The damping vs. temperature curves of deposited films exhibit two peaks which tend to merge into a single peak as the specimen thickness increases above 0.2 µm. The thermally activated anelastic relaxation processes observed on free-standing films are strongly dependent on film thickness, and below a critical value of about 20 µm two anelastic relaxation peaks can be observed; both their activation energy and relaxation strength are affected by film thickness. These results, together with those observed on bulk specimens, are indicative of specific dislocation and grain boundary dynamics, constrained by the critical values of the ratio of film thickness to grain size.

Processing–Structure–Property Relationships in Metals

“…The book gathers manuscripts from academic and industrial researchers with stimulating new ideas and original results. It consists of one review paper regarding state of art and perspectives of alloys for aeronautic applications [1] and fifteen research papers [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] focused on different materials and processes.…”

“…The paper by Campari et al [7] focuses on the change of mechanical behaviour taking place in thin metal films (self-sustained and deposited on a rigid substrate) as their thickness becomes comparable to grain size. The topic is of great scientific interest and practical relevance because thin films have increasing applications in packaging, microelectromechanical systems (MEMS), sensors, and electronic device technologies.…”

XPS investigation of 5N purity Al thin foils for MEMS devices

“…4,5 The quasistatic response of thin foils to external applied stresses has been investigated through microtensile, wafer curvature, 6 microbeam bending, 7 nanoindentation, 8 and bulge tests, 9 while their dynamic behaviorthrough mechanical spectroscopy (MS) tests. [9][10][11][12][13] MS tests are carried out by exciting a material through a periodic stress σ and the occurrence of anelastic phenomena leads to out-of-phase periodic strain ε;…”

“…This work aims to investigate the characteristics of the oxide layer of high purity (5N) Al foils of different thicknesses (10, 50, and 125 μm) by means of X-ray photoelectron spectroscopy (XPS). The samples are the same that have been used in MS tests 12,13 and their microstructural features have been described in Bonetti et al 13 and Cabibbo. 23…”

Dislocation Breakaway Damping in AA7050 Alloy

“…In order to better understand the phenomena occurring during warm deformation of AA7050 alloy isothermal mechanical spectroscopy (MS) measurements have been performed at different temperatures, from room temperature to 185 • C. The knowledge of damping under different conditions of strain and temperature can be useful for solving practical industrial problems [25][26][27][28][29] and investigating basic aspects of materials science [30,31]. Damping is connected to anelastic phenomena occurring in a solid body and its variations provide information about a number of microstructural processes, some of them not detectable by other experimental techniques; the formal theory of anelasticity and an exhaustive description of specific physical mechanisms leading to an anelastic response of a material to an applied stress can be found in the classic book of Nowick and Berry [32].…”