Plastically Deformed Depth In Shot Peened Magnesium Alloys

Author:  Ebihara, Fiore, Angelini
Source:  Conf Proc: ICSP-1, (p.209-216)
Doc ID:  1981052
Year of Publication:  1981
Abstract:  
The shot peened damage depth in three Mg alloys, AZ91, EZ33 and ZE41, was evaluated by acoustic (internal friction), electrical conductivity (eddy current), optical metallography and X-ray diffraction measurements. The internal friction techniques employed included ultrasonic longitudinal wave pulse-echo attenuation, ultrasonic velocity and surface wave attenuation measurements. Surface wave attenuation at 15 MHz proved to correlate best with cold work damage, especially for alloy AZ91A. Electrical conductivity measurements, performed with a commercial eddy current instrument, provided quantitative measure of surface roughness and defined peening damage for the three peening conditions. However, the measurements are indirect and require calibration against a primary signal-damage correlation to give a usable measure of cold work depth. The optical metallographic measurements gave a direct measure of cold work for alloys EZ33 and ZE11. The etches employed were ineffective for AZ91. X-ray diffraction measurements gave a direct measure of damage depth for all three alloys. This method involved successive removal of metal layers by chemical etching until well-defined X-ray patterns were obtained. Descriptors: Magnesium base alloys-- Nondestructive testing; Shot peening; Ultrasonic testing; Eddy current testing; X ray diffraction; Surface structure