Mechanical Engineering Department

Friction stir processing is a new method of changing the properties of a metal through intense, localized plastic deformation ,this process mixes the material without changing the phase (by melting or otherwise) and creates a microstructure with fine, equiaxedgrains, It is used to improve the microstructural properties of metals. In this paper , the enhancement of mechanical propertiesof friction stir welding specimens at variable rotation speeds (1100,1300 and 1500 rpm) with constant feed speed(60mm/min) for 6061-T6 aluminum alloy is studied by using the friction stir processing method at the same variable rotation speed and feed speed in order to transform a heterogeneous microstructure to a more homogeneous, refined microstructure. The best results of the welding line at the parameter 60 mm/min weld speed and 1300RPM rotation speed for the friction stir welding (FSW) and friction stir processing (FSP) where the efficiency reaches to 84.61% for FSW and 89.05% for FSP of the ultimate tensile strength of the parent metal.

Friction stir processing is a may be regarded as new method of changing the properties of a metal through intense, localized plastic deformation ,this process mixes the material without changing the phase (by melting or otherwise) and creates a micro structure with fine, equiaxedgrains, It is used to improve the micro structural properties of metals. In this paper , studying the mechanical properties for 7075-T73 aluminum alloy of friction stir welding and friction stir processing methods at variable rotation speeds (1500,1700 and 1900 rpm) with constant feed speed(40 mm/min). The best results of the welding line at the parameter 40 mm/min weld speed and 1700 RPM rotation speed for the FSW and FSP where the efficiency reaches to 84.61% for FSW and 89.05% for FSP of the ultimate tensile strength of the parent metal .and it is involved a finite element simulation of friction stir processing (FSP) of 7075-T73 Aluminum alloy. Numerical simulations are developed for thermal conductivity, specific heat and density to know the relationship of these factors with peak temperature, The simulation model is tested with experimental results. The results of the simulation are in good comparison with the experimental results.

In this study a Ni-Ti-Cu shape memory alloy was prepared by
powder metallurgy (PM) technique, various compacting pressure
of (600, 700 and 800) MPa and sintering temperature of (850˚C,
900˚C and 950˚C) were used, Shape Effect (strain recovery),
porosity , microhardness ,X-ray diffraction ,energy dispersion xray
(EDX), scanning electron microscope (SEM) , and
differential scanning calorimeter )DSC) tests are conducted to
estimate the effect of different compacting pressure and sintering
temperature on the Ni-Ti-Cu shape memory alloy .The result
showed improvement in hardness and decreasing in porosity with
high compacting pressure and low sintering temperature with
formation of the two main phases austenite and martensite.

 A standard knee-ankle-foot orthosis (KAFO) is typically prescribed to support the limb during locomotion ,during which (KAFO) is used for people with isolated quadriceps weakness or paralysis. In this paper the measurement applied on girl undergoing palsy children in her left leg as a case study. The first pathological concern is of age, weight, length and the residual palsy limb of 30 years old , 59kg, 156 cm, and 76 cm respectively, while the second test done is on man suffering flexion knee and shorten left leg due to injection by a needle in a wrong position when he was a child. The pathological concern is of age, weight, length and the residual defect limb of 35years, 82kg, 172 cm, and 80 cm respectively. This work involves two major parts : the first of which is the experimental part to measure the ground reaction force for both healthy and intake legs. The interface pressure between leg and calf part is measured for twelve points covering the total KAFO surface area , while the vibration data (velocity, acceleration and frequency) are measured at the last stage for the patient at different positions during the gait cycle. The second part is the numerical part during which stresses is calculated using ANSYS software for two cases ,the first one is calculating stresses due to IP loading condition , while the second is calculating stresses due to the harmonic and spectrum vibration type. The above procedures were used for two types of KAFO ,the first one is for metal-metal KAFO type and the second is for the plastic-metal KAFO type. The result shows that the GRF for the healthy person limb is greater than that of the intake person limb in about (17 %) while the healthy limb has GRF lesser than that of the intake limb for the same person in (2.2%) .The Maximum IP is recorded in the posterior regions in the thigh part with (51Kpa) .The result shows that the maximum Vibration data is in the sensing position at the knee on (8.5 and 5.9)for acceleration and frequency respectively at knee region for the plastic-metal KAFO type. Using plastic-metal KAFO type also leads to reduce the vibration data on (6.4 % and 26%)for both acceleration and frequency respectively at thigh region.