Prakt. Met. Sonderband 52 (2018) 253
„49
net Microstructural analysis of powder metallurgy tool steels in the
lm context of abrasive wear behaviour: a new stereological and
~~ experimental study
—
AM Santiago Benito*, Nils Wulbieter*, Fabian Pöhl* and Werner Theisen*
Sing *Lehrstuhl für Werkstofftechnik, Ruhr-Universität Bochum, Bochum, Germany
381 hg rg
a Di
eb Magne;
lndiey Abstract
While microscopes, computers and algorithms available have become increasingly powerful
over the last decade, classic-stereology approaches such as the linear intercept (LI) method
are still widely popular in the specialized scientific literature regarding microstructural
characterization. The results yielded by these procedures are reliable and well understood,
‘Magnets; but the information that can be gathered is limited by its own nature: linear density
Staite, parameters such as the mean free path in the matrix and carbide intercept size do not
Mets wing ~~ explicitly give away details about the shape or size distribution of the hard phases. To
sits of iy ~~ uncover the underlying relations between microstructural traits and abrasive wear
tnoogyefy ~~ behaviour, a broader and more detailed picture of the whole problem is required.
The present work describes the implementation and experimental application of a novel
technique designed to characterize the microstructure of powder metallurgy (PM) tool steels
containing carbide hard phases, with the focus set on its abrasive wear resistance. The
basic principles of the procedure are briefly discussed and the focus of this effort is set on
the data acquisition through single nano-scratch tests and the methods utilized to expose
It spun Rede its relation to the desired properties.
Materials 303
sarth-transition { Introducti
„Introduction
rystal Polyme
nase Wear subjects the affected surfaces to very complex loads due to high multi-axial and in
some cases cyclically occurring stresses. In order to attain an optimal durability for any given
fly Quench application, both the material and the environment, forming the tribosystem, must be
ded Nef properly characterized. Abrasive wear, the main topic of this work, refers to wear due to hard
99. p. 119 particles or hard protuberances forced against and moving along a solid surface [1]. In the
admit case of tool steels, the presence of carbides embedded in a softer metallic matrix gives them
a well-suited and adaptable set of properties to face heavy abrasive environments even at
I Mech Ero high temperatures. Some general rules are employed in (i) the area of product design to
’ select the most convenient material for a given application and in (ii) the field of materials
arth magne and alloy design. Generally, these rules consider all or some of the following parameters:
vs Leit. 201 (i) Mean carbide intercept size, denoted with the symbol d;
(i) Mean free path in the matrix, denoted with the symbol 4; and
mop (i) Volume content of the carbide phase, denoted with the symbol v.
These are usually related to the abrasive particle or groove size Dy, for instance [2]:
> A<Dg<d (1)
1009 Several authors have dwelled on the specific influence of each of these parameters in
different materials and settings.
