ISSN: 1813-0410

Keywords : Aluminum alloy


USING FRICTION STIR PROCESS (FSP) TO IMPROVE THE PROPERTIES OF AA7020 ALUMINUM ALLOY WELDMENTS WELDED BY TUNGSTEN INERT GAS (TIG).

Nashwa Abdul Hammied Saad; Fadhel Abass Hashim; Athraa Hussien Hashim

journal of kerbala university, Volume 11, Issue 1, Pages 50-60

One technique that may be used for repair of defects arising from process upsets is simply re-welding using the nominal process parameters. In such a case, it is important to know whether or not using a different welding process is capable of repairing defects in the already welded material (which will presumably have somewhat different properties as compared to the base metal). To examine this issue , three TIG weld passes were performed in aluminum AA7020 strips(6 piers of strips with 25 *200 *9.5 mm dimension ) by used (Al Mg 5 Cr ) filler metal according to AWS (A- 5.10) standard .Then friction stir weld pass were performed in exiting TIG welds (for only 3 piers of welded strips) with a tool rotation speed of (1000 rpm) and moved straight speed (welding speed ) of (14 m /min). Microstructure and Vickers hardness testes were done for weldments in three regions (base metal , TIG and FSP weld metals) to comparison .
Results indicate that for this material and these conditions weld control parameters its possible to use another welding process to reduce defects in upsets process. Weld metallurgy is only slightly changed in the interface between TIG and FSP structures due to refining in exiting TIG welds structures. While there is no change in metallurgy of other TIG passes and base metal. Hardness in the weld metal after FSP pass increased by about 120% of the base metal.

Influence of Laser and Shot Peening Treatments on Fatigue Properties of 2017 Aluminum alloy.

Hamed. A. Hussein

journal of kerbala university, Volume 10, Issue 2, Pages 189-195

Laser peening (LP) is an emerging surface treatment capable of imparting compressive surface residual stresses and thereby improving the surface resistance of structure to dynamic loading. While the general mechanical concept is similar to conventional shot peening(SP). The present work presents an attempt to illustrate the influence of laser and shot peening on the behavior of fatigue of 2017 aluminum alloy under room temperature and stress ratio (R= -1). The objective of the current work is to evaluate the effect of (LP) and (SP) on the constant fatigue behavior of 2017 aluminum alloy. Also the evaluating of residual stresses at the surface has been conducted. The concluded remarks from this study can be summarized as: At high stresses the (SP) treatment improved the fatigue life by a factor of (35%) while at low stresses this factor becomes (%44%). No improvement effect of (LP) on fatigue life and the lives were reduced by (40%) compared with dry fatigue.