This work, studied the effect of pulse repetition rate on the micro hardness for each of the surface and cross section by using pulsed ND-YAG laser with laser parameters (Energy = 4.12J).The distance off between the output nozzle and the minimum spot size on the surface of sample was (12mm),and pulse duration was (1.8ms).The results showed that the micro hardness increased after laser treatment ,but the micro hardness decreased with increase pulse repetition rate for both the surface and cross section of the pulses. The micro hardness increased as moving away from the molten zone towards the end of the pulses at the heat affected zone due to increase in cooling rate.
In this work the effect of degassing on hardness and microstructure of aluminum recycled cans using aluminum beverage cans scrap from different locations in Baghdad wastes had been studied. Aluminum cans were shredded and ground into small pieces. It was processed through a gas fired to eliminate the coated layer (paint or lacquer on the metal). Generally the scrap is divided into two groups before charging to the furnace, one without adding degassing and the other degased with (Ar-N2). When temperature exceed 690C° molten aluminum was pour into two molds, after cooling. The two ingots were expose to porosity test, hardness, and microstructure. It was found from recycled cans ingot behave like short freezing range alloys. The main form of shrinkage porosity is localized external sink, appeared at the heat centers or at last region to be solidify. This had been verified clearly by microstructure of many regions of the ingot without adding a degasser. Either defect or decrease in hardness was clearly seen in the ingot without degassing addition. In addition to oxides, a number of additional compounds could be considered inclusions (intermetallic phase particles) in cast structures. Where the main conclusion was to remove gases without using a degassing to ingot decadence on the first gas fire on the cans to remove all paint or lacquer on the metal, but this was not sufficient and properly we need to add degassing to ingots. Finally this was clearly shown from the results of the ingot with adding a degassing had 89 kg/mm2 HV rather than 61 kg/mm2 for ingot without degassing
Some mechanical properties of mortar (compressive strength and hardness) with sawdust replacement of sand were investigated. Cubes of 50 mm × 50 mm were prepared, the compressive strength tests were done for a replacement levels ranging (5, 10, 15, 25, 50, 75) % by volume a reference mix were also prepared for comparison this test was done after 7, 14, and 28 days while hardness test were done after 28 day for a replacement levels (0, 5, 10, 15, 25) % by volume. Result showed that the compressive strength of the specimen were decreased with higher sawdust content, hardness values were decreased slightly in the replacement levels 0, 5, 10 % while the values began to decrease noticeably in the replacement levels 15 and 25 % the hardness values were (59, 57.5, 56, 47.77 , 45.2) N/mm2 respectively A cost analysis was done, this analysis was based on a unit of mortar (1.0 m3) made from conventional materials and a modified concrete made by substituting materials with sand using sawdust
The aim of this article is to investigate the properties for joints of welded martensitic stainless steel (MSS) by ER 309 L filler wire, using tungsten arc welding (Tig). The regions of the base and welded materials were investigated by means of SEM, EDS, OP and HV were conducted to calculate the properties of the welded specimens. The influence of heat and cryogenic treatments also investigated, The best results from microstructure side occurrence epitaxial grains growth which was observed along the interface of weld-metal region, the maximum hardness was (414 HV) in conventional heat treated samples that tempered at 200°C, precipitation of small carbides were observed that this is responsible for the improvement in the mechanical properties of the material. Hardness at the HAZ region in state of DCT in all weldments was reduced as compared to hardness of HAZ region of CHT. The microhardness was at the highest value in the fusion zone
The porous Titanium is characterized by high permeability which can assure the ingrowth of bone tissues, and consequently results in a good bonding between the metallic implant and the bone. In this work, Silicon element was added to the Commercially Pure Titanium at different weight percent of (2, 4, 6, 8 and 10) to investigate its effect on the porosity percentage, mechanical properties of the resulted samples. XRD analysis stated that at (Si) content lower than (2 wt%) the alloy is single phase (α- Ti alloy), as the Silicon content increased, in addition to (αphase), (Ti5Si3) intermetallic compound developed in the alloy. Porosity measurement results showed that the porosity percentage increases with the increase in Silicon content. Wear results stated that the wear rate increases with the increase in silicon content due to the increase in porosity percentage while the hardness results stated that there is no significant effect for Ti5Si3 intermetallic compound on improving the hardness of the samples. This is attributed to its low percent and the major effect of porosity on hardness which declined the effect of Ti5Si3 by reducing the hardness of the alloy compared with the master sample. The obtained results of the (yield strength, ultimate compressive strength and Young’s modulus) were within the values that match bone’s properties. This means these materials are suitable for biomedical application
This paper is aimed to study the effect of SiC addition as reinforcement to 6061 T6 alloy. Al 6061 T6 alloy SiC composites were prepared by melting the alloy in a vortex and adding 4 % and 10% weight fractions of SiC. Then pouring the mixture into a mould to obtain a bar of 12 mm diameter and 150 mm length. Wear specimens were manufactured in dimensions of 20mm x 10mm according to ASTM to the base alloy and the cast matrix alloy. Microstructure have been carried out to understand the nature of structure and Hardness test also implemented to specimens. Adhesive wear test have been conduct both on the alloy and composites at different parameters (time, load and velocity). From the obtained results, it was found that wear resistance improved during the carbide addition comparing with the base alloy as a result of SiC addition which contributed in improving the hardness of the alloy that reflects to the wear resistance and these properties were improved as the increasing of the carbide silicon percentage.
Silica particles are directly introduced into polyurethane resin with different grain size and different volume fractions to obtain a new composite. Hardness, impact strength (charpy) and compression properties were studied with the conditions mentioned; Acid solutions and UV- radiation were the main environments studied on the samples prepared. The results showed that the acid affected the properties more than UV- radiation
This study assessed the temporal and spatial water quality variability to reveal the characteristics of the Shatt Al-Arab River, Basrah, Iraq. A total of 14 water quality parameters (water temperature (T), pH, electrical conductivity (EC), Alkanets (Alk), total dissolved solids (TDS), turbidity (Tur), total hardness (TH), calcium (Ca), magnesium (Mg), chloride (Cl), sulphate (SO4), total suspended solids (TSS), sodium (Na), and potassium (k)) were analyzed Use of multivariate statistical methods in a total of three stations for the period 2016-2017. In this study was use a statistical approach to determine the water quality using the Pearson Correlation Index (PCI), Principal component analysis (PCA), and Factor Analysis (FA) were used to analyze the data. Main water pollutant sources were wastewater from agricultural drainage and industrial wastewater. Significant relationships recorded between the investigated parameters based on the results of PCI, at the 0.01 and 0.05 significance levels. Per the FA results, 77.1 % of the total variance explained by two factors.