Measuring Residual Stresses in Aluminum Engines Using Neutron Diffraction Techniques
This research project explores the measurement of internal stresses in aluminum engines through neutron diffraction methods. By utilizing neutrons, which can penetrate several centimeters of aluminum without significant absorption, we analyze the residual stresses formed during the solidification of casting alloys. The project covers the principles of diffraction, crystal lattices, and the experimental design required for accurate data collection and analysis. Understanding these internal stresses is crucial for improving the performance and durability of aluminum engine components.
Measuring Residual Stresses in Aluminum Engines Using Neutron Diffraction Techniques
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Presentation Transcript
Internal Stresses in Aluminum Engines Neutrons DRSA Inreach
Measuring Residual Stresses • Introduction of research project • Solidification of casting alloys • Stresses and strains • Crystal lattices • Diffraction • Neutrons • Experimental design • Data • Analysis of data
What Waves Will We Use • Wavelength about 2 Å • Go through several cm of Al
Possible Waves • Light • Wrong wavelength, absorbed • X-rays • Wavelength OK, strongly absorbed • Electrons • Wavelength OK, very strongly absorbed (penetrate less than a mm) • Neutrons • Wavelength OK, able to pass through many cm of Al • We chose neutrons
What is a Neutron? • Subatomic particle • Discovered in 1932 • Electrically neutral • With protons, they form nuclei • Stable in the nucleus • Unstable when free, half-life 10 minutes and 11 seconds when free, beta decay (neutron turns into a proton, electron and electron antineutrino) • Able to penetrate matter because electrically neutral • About the same mass as a proton
What makes the Reactor Go? • Fuel is metallic composite containing uranium enriched in U235 • U235 is a fissile isotope of uranium • So what does fissile mean?
What makes the Reactor Go? • So answer the question, what makes the reactor go? • A chain reaction…
What makes the Reactor Go? • Then what’s all the water in there for? • Neutrons ejected from fission are going too fast for U235 nuclei to capture them. • The water slows them down.
Bragg’s Law Sample Reactor
Next Week… • …how do we design an experiment using neutrons
