Date of Award

May 2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Yachao Y. Wang

Abstract

This abstract focuses on the treatment of three distinct materials: 17-4 PH stainless steel, a nickelbased super alloy, and AISI 4140 stainless steel. The treatment process involves a combination of laser deposition and ultrasonic impact peening.

The study explores the effects of this treatment on the mechanical and microstructural properties of the mentioned materials. Laser deposition is utilized to enhance surface characteristics, such as hardness, wear resistance, and corrosion resistance. Nickel-based super alloys are known for their exceptional high-temperature strength and corrosion resistance, making them suitable for demanding applications in aerospace and power generation industries. AISI 4140 stainless steel is widely used in engineering applications due to its high tensile strength and toughness. Ultrasonic impact peening, on the other hand, is employed to induce residual compressive stresses in the treated materials, thereby enhancing fatigue resistance and reducing the risk of crack initiation. The combination of laser deposition and ultrasonic impact peening offers a synergistic approach to improving the properties of these materials, making them more suitable for challenging operating conditions.

The research involves a comprehensive characterization of the treated materials using techniques such as X-ray diffraction, microhardness testing, and electron microscopy. The results demonstrate significant improvements in surface properties and subsurface microstructures, highlighting the potential of this treatment approach for a wide range of industrial applications.

In summary, the study underscores the effectiveness of combining laser deposition and ultrasonic impact peening as a means to enhance the mechanical and microstructural properties of 17-4 PH stainless steel, nickel-based super alloys, and AISI 4140 stainless steel. This research contributes to the understanding of advanced surface modification techniques for engineering materials, offering insights into their potential for optimizing material performance and extending component lifetimes.

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