ISSN: 1999-8716

Keywords : Aluminum alloy


EXTRUSION BEHAVIOR OF WROUGHT AND AS-CAST AL-5.5%ZN-2,5%MG ALLOY AT DIFFERENT TEMPERATURES AND REDUCTIONS USING SQUARE DIE ANGLE.

Kadhim Mijbel Mashloosh

DIYALA JOURNAL OF ENGINEERING SCIENCES, 2016, Volume 9, Issue 3, Pages 90-103

Laboratory scale extrusion experiments were carried out on AA7075 billets. Two groups of wrought and homogenized as-cast (Ф 25 X 60) mm cylindrical billets were used. Each billet was cut longitudinally into halves, the two mating surfaces were polished and scribing an orthogonal network of furrows (0.1 mm wide and 0.3 mm deep) onto one of the faces. The network formed was as a square grid of 1 mm spacing. The two halves were put together and partially extruded, removed from the die, separated along the same plane and the grid distortions were observed.
16 experiments were carried out on each group of wrought and as-cast billets. Each group 3 6 was extruded at four different pre-heating temperatures (350, 400, 420, and 450) oC. Four values (60, 70, 78, 95.6) % of percentage reduction in cross sectional area were used at each temperature. The ram speed was 4.6 mm/sec. A mixture of graphite powder and grease was 40 used as a lubricant.
The usual type consisting of a single maximum in the transverse grid lines located at the extrusion axis was occurred in all the experiments of both groups.
Microstructure tests were done on the other half after it has been extruded for all the billets of the two groups. Five positions were taken for the microstructure. The magnitude of the maximum load needed for the experiments was reported for both wrought and as-cast billets.

EXPERIMENTAL FATIGUE STUDY of 6061 – T651 Aluminum ALLOY UNDER ALTERNATING ROTATING BENDING LOADING

Basim Hussein Abbas

DIYALA JOURNAL OF ENGINEERING SCIENCES, 2013, Volume 6, Issue 4, Pages 1-13

Fatigue under constant and variable cyclic stresses of 6061 – T651 aluminum alloy was studied at room temperature using pure bending as a loading test. An empirical model was derived from the experimental data of surface crack lengths for short and long fatigue cracks and the corresponding number of cycles. Variable cyclic stresses test was carried out using three specimens of the same material. The proposed model was applied to estimate the life of specimens and it showed that good results can be predicted (under – estimate the life of the specimens), and gave good indication for warning before failure happens. From this study it was concluded that there is no need to establish the S-N curve of the material.

STUDY OF PITTING CORROSION BEHAVIOR FOR ALUMINUM ALLOY 1100 IN 3% NaCl SOLUTION

em A. Karim; Abdul Mun

DIYALA JOURNAL OF ENGINEERING SCIENCES, 2009, Volume 2, Issue 1, Pages 1-27

Pitting corrosion behavior of aluminum alloy 1100 was studied in this investigation in a neutralized and aerated 3% NaCl solution and all experiments were performed at room temperature. There were four groups of specimens to be studied: 1. As received, 2. Annealed at 760 oC, 3.Cold 35% rolling, and 4. 75% rolling.
Numbers of pits was countered, and pits depth was measured by used digital photo fixed on a microscope a digital photos were taken
The numbers of pits increase as duration increase within the period of (5-90) days. The graduation of increasing is mostly uniform for all groups' leads to the conclusion that nucleation and initiation of pits are continuing with the continuity of pits growth. Also it was observed that the annealed specimens have the lowest tendency (0%) to corrode by pitting and this tendency increase forwarding as follows:
Annealed < as received < rolling 35 %< rolling 75%.
Also it was observed that maximum depth of pitting increases gradually with duration for all groups. Also it was proved that metallurgic factor (cold rolling) increase with increase pits number, maximum pit depth and pit growth towards depth. Probability of pits appear was observed to be increased with duration for all groups and it is high expected for the shallow pits, in contrast for the deep pits.
Through the examination of pit's normal distribution due to its number and depth, it was concluded that the recent pits depth and due to their high rate of growth will reach the same depth of the recent one leads to a mean value of depth for all. It was concluded that morphology and concentration of pitting are function of duration and specimen treatment. Pitting concentration increases with duration.