Manuel Acosta

The University of Texas at El Paso
UTEP
Resume
Senior Project Progress Presentation

Project Title: Oxidation Behavior of RuAl Alloys
Advisor: Dr. David R. Johnson
MSE/Purdue University

Introduction

RuAl Phase Diagram (B. Tyron) -- RuAl is an intermetallic compound often considered a good candidate for high temperature applications. It has a B2 structure and melts at approximately 2060oC.Combines good ductility, oxidation, strength and thermodynamic properties.

Objectives

  • To describe and compare the oxidation behavior of alloys containing Ru, Al, Mo and Cr produced in different compositions by the tri-arc, arc-melting, floating and induction methods.
  • Study the type of oxide formed and its oxidation resistance
  • Compare samples in terms of their fracture toughness and oxidation resistance using data previously obtained by T.D. Reynolds and D.R. Johnson.

Approach

  • Cyclic oxidation tests at 1100oC
  • Determine loss of mass per surface area
  • Characterize oxide scales by microscopy and XRD
  • Characterize the change in microstructure in the scale/matrix interface by SEM/EDS.

Findings

  • Mo samples showed poor oxidation behavior (non-protective scale)
  • Loss of weight in Mo samples due to MoO3 vaporization and spoliation
  • Cr samples demonstrated good oxidation behavior (protective scale)
  • Binary RuAl has a good oxidation behavior, but is a brittle material, Oxidation process occurs mainly in the eutectic region forming a thin layer of Ru and Al, Aluminum is lost
  • Cr samples shown the best fracture toughness and oxidation resistance.
 
Figure 2: 50X micrograph of the oxide
scale for a Ru-Al-Mo alloy.
1000X SEM image of the scale/matrix
interface of a Ru-Al-Mo alloy.

Recommendations

  • Further characterization of the oxide /matrix interface in the Cr and RuAl samples
  • Make same procedure for different cyclic oxidation temperatures
  • By getting rid of eutectic in binary, RuAl oxidation resistance is improved.

Links to UTEP