Soft Surface Layer of Age-Hardened Al-Zn Alloys and Its Effect on the Fatigue Strength

Teruto Kanadani; Keiyu Nakagawa; Norio Hosokawa

doi:10.4028/www.scientific.net/KEM.345-346.391

Paper Titles

On the Fatigue Crack Growth Behavior of a Nitrided and Shot Peened Steel
p.375

Fatigue Crack Initiation in Crystalline Materials – Experimental Evidence and Models
p.379

Effect of Temperature on the Low Cycle Fatigue of Cast Inconel 792-5A
p.383

Application of Notch Strain Approach to Evaluate Fatigue Life of Construction Equipment
p.387

Soft Surface Layer of Age-Hardened Al-Zn Alloys and Its Effect on the Fatigue Strength
p.391

Two Methods for Determination of Fatigue Crack Propagation Limit Curves and their Application for Different Materials
p.395

Fracture Assessment of Flaws in Weldments using FITNET FFS Procedure: An Overview
p.401

Alignment and Combination Rules on Multiple Flaws in Fitness-for-Service Procedures
p.411

Failure Assessment Diagrams for a Solid with a Crack or Notch under Uniaxial and Biaxial Loading
p.417

HomeKey Engineering MaterialsKey Engineering Materials Vols. 345-346Soft Surface Layer of Age-Hardened Al-Zn Alloys...

Soft Surface Layer of Age-Hardened Al-Zn Alloys and Its Effect on the Fatigue Strength

Abstract:

The surface layer of binary Al-Zn alloy specimen, ever after a long time aging, remains softer than the interior when the specimens are age-hardened at around room temperature after quenching from high temperature. In this study, effects of the soft surface layer on the fatigue strength of Al-Zn alloys were studied under repeated tensile loading. Vickers microharhness test revealed that there existed less hardened region in the vicinity of grain boundary and specimens surface, and that the region extends 50 to 100μm from the surface inward. From the plot of the stress amplitude against the number of cycles to failure, it is concluded that the presence of less hardened surface layer increases fatigue resistance of age-hardened Al-Zn alloys containing 8 to 16 mass%Zn under the repeated tensile loading.