Ses sion I Monday, September 4-afternoon I1 MICROSTRUCTURE AND FUNCTIONALITY OF MATERIALS INTERFACES XRD VS. PHOTOLUMINESCENCE A NEW CLASS OF DEVICES TO CALIBRATE DEFORMATION POTENTIALS
Müller, W Gindl-Altmutter, J Konnerth, G Maier, M Bartosik, R Dan Iel, C Mitterer, G Maier, W Ecker, J Vila-Comamala, C Da Vid, S Schoeder
(+13 others)
2015
J. Keckes, Sci. Rep
unpublished
Al though in ter faces rep re sent only a small vol ume frac tion of bi o log i cal and man-made ma te ri als, their in flu ence on func tional prop er ties like frac ture tough ness, hard ness and over all me chan i cal in teg rity is de ci sive. In this con tri bu-tion, the re la tion ship be tween microstructure and me chan i-cal prop er ties of in ter face-based ma te ri als like wood, mul ti lay ered thin films and ce ramic nanocomposites is discussed on the bases of ex per i men tal data,
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... ob tained us ing syn chro tron X-ray dif frac tion and trans mis sion elec tron mi cros copy tech niques. The re sults dem on strate that us ing clever microstructural and in ter face de sign it is pos si ble to en hance me chan i cal prop er ties of ma te ri als sig nif i cantly. First, the microstructure of a mac ro scopic branch-stem in ter face of Nor way spruce is ana lysed us ing wide-an gle X-ray dif frac tion and eval u ated mag ni tudes of the micro-fibril an gle are cor re lated with var i ous pro tec tive mech a-nisms op er at ing at dif fer ent length scales. It is de mons-trated that wood ad justs the cel lu lose fi bre tex ture in or der to pro tect both the stem and the branch from structural damage. In or der to un der stand the func tion al ity of mi cro-and nano-scopic in ter faces, cross-sec tional syn chro tron X-ray nanodiffraction ex per i ments on thin films are per formed at ID13 and P03 beamlines of ESRF and Petra III, re spec-tively. By com par ing cross-sec tional dis tri bu tions of phases, tex ture, crys tal lite size and strains, it is pos si ble to un der stand the in flu ence of dis tinct thin film re gions on the over all and lo cal me chan i cal re sponse of the films. In-situ dif frac tion ex per i ments com bined with in den ta tion are used to de ter mine microstructural changes and stress con-cen tra tions accompanying various fracture modes. Fi nally, a com bi na torial re fine ment of microstructure, prop erty and pro cess con di tions at graded TiAlN thin film cross-sec tions is per formed us ing X-ray nanodiffraction in or der to iden tify in ter face micro struc tures with the high est hard ness. The micromechanical and X-ray dif frac tion ex-per i ments are per formed iteratively in three steps and are ap plied as a ba sis to de sign novel types of coating materials. In the last sev eral years many meth ods have been es tab-lished to ma nip u late the op ti cal prop er ties of III-V semi-con duc tors which are a very prom is ing ma te rial class for non-clas sic quan tum light sources [1]. One highly ef fec tive pos si bil ity to change their band struc ture (e.g. or der of LH/HH bands), which de fines the op ti cal prop er ties, is to get full con trol of the strain/stress ten sor. The de for ma tion po ten tials de scribe the changes in the band struc ture upon vari a tion of the ap plied strain. A ver sa tile way to con trol the strain state is to bond a semi con duc tor mem brane onto a pi ezo elec tric car rier mate rial. By ap ply ing an elec tri cal field to the car rier and there fore, mak ing use of the in verse pi ezo elec tric ef fect, strain acts on the mem brane. This ap proach has al ready
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