Materials Science and Engineering Location: Wilsdorf Hall 200 and Zoom
Add to Calendar 2021-12-03T10:00:00 2021-12-03T10:00:00 America/New_York Doctoral Dissertation Proposal - Trevor K. Shoemaker Fatigue and Environmentally Assisted Cracking Behavior of Wrought and Additively Manufactured 17-4PH Stainless Steel   Committee Members: Ji Ma, MSE, Chair James T. Burns, MSE, Advisor Sean R. Agnew, MSE John R. Scully, MSE Xiaodong (Chris) Li, MAE Abstract: Wilsdorf Hall 200 and Zoom

Fatigue and Environmentally Assisted Cracking Behavior of Wrought and Additively Manufactured 17-4PH Stainless Steel

 

Committee Members:

  • Ji Ma, MSE, Chair
  • James T. Burns, MSE, Advisor
  • Sean R. Agnew, MSE
  • John R. Scully, MSE
  • Xiaodong (Chris) Li, MAE

Abstract:

Metal additive manufacturing (AM) is an attractive technology that can directly produce complex part geometries with just feedstock material and an AM machine. The 17-4PH stainless steel alloy has received significant attention as an AM feedstock material for its combination of high strength and moderate corrosion resistance. To date, research on AM 17-4PH has focused on microstructure and first order properties like strength and ductility with little emphasis on environmental performance. Four research tasks are proposed to evaluate the effect of environment on the fatigue and fracture performance of AM 17-4PH, produced using the laser powder bed fusion (LPBF) AM process, through comparison with its traditional, wrought counterpart. Material thermal processing protocols, mechanical properties, and the effects of high temperature heat treatments (e.g., hot isostatic pressing (HIP)) on porosity are evaluated in Task 1. Task 2 compares the stress corrosion cracking performance of wrought and AM 17-4PH in 0.6M NaCl under anodic, cathodic, and open circuit potential conditions with a focus on hydrogen dominated fracture. Task 3 evaluates the corrosion fatigue crack growth behavior of wrought and AM 17-4PH in humid air and 0.6M NaCl at various applied potentials. Task 4 investigates a fatigue crack path instability phenomenon encountered in wrought 17-4PH through constant stress intensity range testing, microstructural, and residual stress characterization. The results from this research will provide a survey of the environmentally assisted cracking (EAC) performance of AM 17-4PH and identify the persistent, microstructural features introduced by AM that control its EAC performance. 

Zoom Info:       

(In-Person Attendance Preferred)

https://virginia.zoom.us/j/95959422769?

Meeting ID: 959 5942 2769 

Please e-mail Trevor for the passcode: tks7c@virginia.edu