Prakt. Met. Sonderband 38 (2006) 161 
APPLICATION OF FIB FOR METALLOGRAPHIC PREPARATION 
OF Cu-Al-Ni MELT-SPUN RIBBONS 
spared by 
ussed ion ror ; = Ed . ve nr 
Franc Zupani&*, Elfriede Unterweger**, Albert C. Kneissl*, Ivan Anzel*, Gorazd Lojen 
‚preparec * University of Maribor, Faculty of Mechanical Engineering, Smetanova 17, 
epend on . . : 
, particles Si-2000 Maribor, Slovenia ) 
: ** Montanuniversitit Leoben, Lehrstuhl fiir Metallographie, Franz-Josef-Strasse 18, 
Ss close to A-8700 Leoben, Austria 
alyzed in ’ 
5 and the 
ul tool for 
ons. The ABSTRACT 
g and 3D- ; . : 
ar the free Scanning electron microscopes equipped with focussed ion beam systems (FIB) have found 
many interesting applications in recent years. Typical FIB uses accelerated Ga-ions for 
horizontal cutting materials, making cross sections (3D-microscopy), preparing TEM samples, ion 
n, since it imaging, etc. Impingement of heavy Ga-ions with sample atoms produces avalanche of 
different processes resulting in sputtering of surface atoms, implantation of Ga-ions into the 
avoidable, surface layer, production of defects and even surface amorphisation. In polycrystalline 
“structural and/or heterogeneous materials is the removal of surface layers anisotropic. The sputtering 
rates of different phases are not equal and, in addition, they also depend on crystal 
orientation. These features can be very useful in metallographic preparation of samples. 
Namely, uneven ion-etching can produce appropriate contrast between dissimilar phases 
and between differently oriented crystal grains. 
The Cu-Al-Ni shape memory alloy ribbons produced by melt-spinning may be martensitic or 
consist of martensite and y.. Application of standard metallographic procedures and 
Sci. Eng., etchants posed several problems. Therefore we decided to investigate the possibilities of 
application of FIB in metallographic preparation of one- and two-phase microstructures. The 
s”, Mater. main goal was to optimise FIB preparation of polished cross-sections as well as of both 
surfaces of melt-spun ribbons. Microstructure could be revealed on all surfaces, but the 
2nt during finest details could be resolved only on clean, mechanically polished surfaces. Large ion 
current revealed the microstructure on large areas very quickly, but on the expense of 
, Higher details. Therefore a compromise should be made between operating time, size of 
4, p. 139- investigated area and the resolution of details. The most important conclusion is: The 
microstructure of melt-spun ribbons can be revealed using a combination of FIB-etching and 
Ss science 3D-microscopy without any need of classical metallographic preparation. 
eering 27 
1 INTRODUCTION 
ng to the 
308-309, Traditional metallographic preparation of samples for optical microscopic investigations 
and for the scanning electron microscope (SEM) most frequently consists of hot or cold 
ournal of mounting, grinding, polishing and, finally, etching. For small samples like melt-spun 
„ ribbons, mounting in resin is unavoidable. Therefore, as a rule, only one surface (or cross- 
ater”, 40, section) of each small sample can be prepared and investigated. 
The metallographic preparation of Cu-Al-Ni shape memory alloy (SMA) melt-spun ribbons 
is afflicted with problems from the very start. Already the as-cast ribbons may appear fully 
martensitic or can. depending on the chemical composition, be partially martensitic.