Tag Archives: Hardness.

The Influence of Strontium On the Hardness and Impact Strength of Eutectic Al-Si+1.0% Manganese Alloy (Published)

This paper studies the effect of strontium on the hardness and impact strength of aluminium-1.0%manganese-12%Si alloy. Aluminum and its alloys are gaining a wider industrial importance because of their physical and mechanical properties which includes high specific strength, high wear resistance, high temperature strength and controlled thermal expansion coefficient. In this research, strontium was added at various compositions to the percentage of silicon present in the alloys (12% of Si; 0.02-0.03% of Sr) and 1.0% manganese which serves as a modifying agent). A calculated mass of the aluminum and silicon were melted and cast as cylindrical ingots. Hardness and impact test were carried out using charpy impact test machine for impact test and Rockwell hardness testing machine (ASTM E18-11) used to measure the hardness test. The results showed that the addition of strontium to eutectic Al-Si alloy modifies the Al-Si eutectic morphology with significant improvement in mechanical properties of the alloy.

Keywords: Hardness., Impact Strength, aluminum alloy, eutectic alloy, strontium

The Effect of Newly Prepared Cleansing Agent on the Hardness of Highly Impact Acrylic Denture Base Material (Published)

This research study is aimed to evaluate the effect of two prepared and two commercial solutions on Hardness of high impact acrylic denture base material. The total number of specimens was seventy five. They were prepared from high impact acrylic and subdivided into five groups for each solution (EDTA, Soda+H2O2, Lacalut, Corega and distilled water). Indentation hardness test was applied for this research. The specimens were constructed with dimensions 30×15×3± 0.03mm (length, width, and thickness respectively) According to ADA specification number.   The immersion periods in this research area (2day, 7 days and one month).  ANOVA and Duncan multiple range test were used. The statistical results were considered significant at p ≤ 0.05. The results show that there were significant differences in indentation hardness in all solution that use specially in (EDTA) and lacalute  causes decrease of hardness of high impact acrylic material in (2days, 7 days, and one month). It was concluded that (EDTA) and lacalute denture cleanser have the most effect (decrease in the indentation hardness) of high impact acrylic denture base material in (2days, 7 days, and one month)

Keywords: Corega, Denture Cleanser, Hardness.

Effects of Human and Animal Urine on Nitriding for Improved Hardness Property of Aluminium Alloy Materials (Published)

The study was carried out to determine the effect of human and animal urine on nitriding for improved mechanical properties of aluminium alloy material. The study adopted a 2×3 factorial design. The population comprised alloy materials that contain aluminium as elemental metal in its content. The specimens of 24 pieces of aluminium alloy materials were cut from 70mm diameter aluminium alloy machined to 50mm diameter. Human urine was obtained from urine houses built in Port Harcourt while animal urine was got from cattle butchers also in Port Harcourt. Twelve specimens were heated to a temperature of 5000C in a cylinder containing human urine for 4, 5, and 6 hours respectively while another 12 specimens were also heated to the same temperature in a cylinder containing animal urine for 4, 5 and 6 hours respectively. In either case, no quenching was applied, rather the materials were allowed to cool naturally. Direct testing and measurement of nitrided specimens were carried out using Brinell testing machine. The research question that guided the study was answered using mean while the null hypothesis was tested using Analysis of Covariance (ANCOVA) at 0.05 level of significance. It was found from the study that human and animal urine as local ammonia increased the hardness of aluminium alloy material. Animal urine is more effective than human urine on nitriding, nitriding time showed significant effect on hardness of aluminium alloy material.

Keywords: Aluminium Alloy, Ammonia, Hardness., Nitriding, Urine