Improved High Cycle Fatigue Damage Tolerance of Turbine-Engine Compressor Components by Low Plasticity Burnishing

Abstract

Significant progress has been made in the application of low plasticity burnishing (LPB) technology to military engine components, leading to orders of magnitude improvement in damage tolerance. Improved damage tolerance can facilitate inspection, reduce inspection frequency, and improve engine operating margins, all leading to improved military readiness at significantly reduced total costs. Basic understanding of the effects of the different LPB process parameters has evolved, and finite element based compressive residual stress distribution design methodologies have been developed. By incorporating accurate measurement of residual stresses to verify and validate processing, this combined technology leads to a total solutions approach to solve damage problems in engine components. An example of the total solution approach to develop LPB processing of a 1 st stage Ti-6Al-4V compressor vane to improve the foreign object damage (FOD) tolerance from 0.002 in. to 0.025 in. is presented. The LPB process, tooling, and control systems are described, including recent developments in real-time process monitoring for quality control. Performed on CNC machine tools, LPB processing is easily adapted to overhaul and manufacturing shop operations with quality assurance procedures meeting military and industry standards, facilitating transition to military depots and manufacturing facilities.

Fatigue life of additively manufactured Ti6Al4V scaffolds under tension-tension, tension-compression and compression-compression fatigue load

“…For σ m < 0, three different regimes emerge: (i) for σ a > 16 MPa the slope of the curve is positive, (ii) for σ a between 12 and 16 MPa the curve is horizontal and (iii) for σ a < 12 MPa the slope is negative. Only the last region corresponds to the behavior of bulk Ti6Al4V, where a higher stress amplitude is required to obtain the same fatigue life when the mean stress is decreased 37 , 38 . As highlighted by De Krijger et al ., who studied the effect of different stress ratios on the fatigue behavior of scaffolds under compression-compression fatigue, Haigh diagrams for porous and non-porous Ti6Al4V can deviate notably 39 .…”

Multiparametric Optimization of Low Plasticity Burnishing Process for AISI 4340 by using Utility Concept

“…Most of the research work on LPB is done by Paul S. Prevey.Preveyshowed the effect of residual stress and percentage of cold work on depth of compressive layers and residual stresses for material IN718, Ti-6-4 and 17-4 PH steel [2].LPB is also found to improve high cycle fatigue dimension and tolerance of Ti6-Al-4V turbine engine compressor [3]. P.R.…”

Joining metrics enhancement when combining FSW and ball-burnishing in a 2050 aluminium alloy

“…To this end, the ball-burnishing technique is a potential solution that can enhance the surface properties by deforming the welding area that commonly presents different thermomechanical affected zones. In particular, Prevey et al [7] investigated the fatigue improvement of aluminium alloys firstly welded by FSW and later low plasticity burnished as a final surface treatment. They stated that the burnishing process induces compression residual stresses which tend to improve the fatigue behavior of the component.…”