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Oral Poster

Qualitative studies on vibration induced cavitation loading at bulk materials and coatings

Tuesday (21.02.2017)
18:03 - 18:06
Part of:


Vibration induced cavitation loading can lead to damages on pump components, valves, and 

cylinder liners. Both the efficiency and the life time of affected components are reduced by the 

extensive mechanical and corrosive loads. Cavitation tests, like the vibratory apparatus (ASTM 

G32-16), are important material-scientific techniques. By verifying cavitation resistant materials 

or understanding basic wear mechanisms and failure modes by means of cavitation tests, costs 

for maintenance, reparation or replacement of affected components can be reduced.  

Cavitation  has  always  a  geometrical  impact  on  the  component  surface.  Depending  on  the 

material,  cavitation  loading  causes  deformation,  pitting,  cracking  or  fatigue  wear.  Coatings 

could  delaminate  or  flake-off.  These  surface  alterations  in  turn  influence  the  formation  of 

cavitation bubbles in terms of size, speed and impact pressure so that the cavitation intensity 

and the cavitation erosion is significantly affected. To ensure a testing which fits service-like 

demands, an estimation of the cavitation intensity, for example in terms of correlation factors, 

would be a major advance and is therefore a primary aim of the current investigations.  

The investigations focus on the impact of cavitation on the bulk materials EN-GJL-250 (gray 

cast iron  with lamellar  graphite)  and EN-AW-2024  (age-hardened aluminium-copper-alloy). 

EN-GJL-250 is a widely used pump material because of low costs and easy machinability. The 

EN-AW-2024 alloy is a soft light weight construction material, which is often used in aerospace 

and  aircraft  constructions.  As  a  coating  material  a  highly  corrosion  resistant  and  ductile 

electroplated nickel coating is investigated. Due to the different properties of these materials 

different  wear  mechanisms  and  failure  modes  for  cavitation  induced  fatigue  stress  can  be 

observed.  To determine the influence of several parameters on cavitation, the materials are 

tested with a vibratory apparatus (ultrasonic oscillator), using the direct and indirect set-up. 

Beside  the  variation  of  vibration  amplitude  and  distance  between  vibrating  surface  and 

specimen,  the  influence of  the  gas-content of  the  used medium  on the bubble formation is 

investigated.  In  addition  material  dependent  measurement  intervals  and  test  durations  are 

specified. These measurements are intended to characterise and quantify the fatigue behaviour 

of EN-GJL-250, EN-AW-2024 and the nickel coating. The surface characterization is performed 

with  tactile  roughness  measurement,  metallography,  3D-microscopy  and  scanning  electron 

microscopy.  

 

 

 

 

Speaker:
Jennifer Honselmann
Technical University of Darmstadt
Additional Authors:
  • Marius Siebers
    Technische Universität Darmstadt
  • Herbert Scheerer
    Technische Universität Darmstadt
  • Georg Andersohn
    Technische Universität Darmstadt
  • Matthias Oechsner
    Technische Universität Darmstadt