In situ composites have been studied mainly to eliminate wettability, porosity and non-uniform distribution of particulate problems in composite materials. Al-Mg 2 Si alloy are preferred choice of such group of alloys owing to the combination of light weight and improved mechanical properties. The morphology of Mg 2 Si is one of the key parameters for the wear properties. In this work, squeezed casting method was used to produce samples where porosity was aimed to be reduced and morphology of Mg 2 Si was altered. In addition, the wear properties of in situ A380-Mg 2 Si were investigated. It was found that as squeeze pressure was increased, porosity and size of Mg 2 Si was decreased and wear rate was increased.

Gözenekli silisyum (GS) üretim yöntemi olan, elektrokimyasal aşındırma (anadizasyon) koşullarının, Metal-Gözenekli Silisyum Direk Hidrojen Pili (Metal-GS-DHP) elektriksel parametrelerine etkisi oldukça yüksektir. Bu çalışmada 4 temel anodizasyon koşuluyla (zaman, akım yoğunluğu, hidroflorikasit:su  oranı ve Işık), n tipi, (111) yönelimli, tek kristal silisyum kullanılarak GS üretilmiştir. Anodizasyon zamanı 5-100 dakika, akım yoğunluğu 5-75 mA/cm2, HF:deiyonize H2O oranı 1:1- 1:11 ve ışık şiddeti 1000-7000 lüx aralıklarında uygulanmıştır .En iyi anodizasyon zamanı 40 dakika ve buna karşılık gelen Metal-GS-DHP elektriksel pil parametreleri, Voc= 590 mV Isc=30 mA’dir. En iyi  akım yoğunluğu  20 mA/cm2 ve buna karşılık gelen Metal-GS-DHP elektriksel pil parametreleri, Voc= 700 mV, Isc=15 mA’dir. En iyi  HF:H2O oranı 1:3 ve buna karşılık gelen Metal-GS-DHP elektriksel pil parametreleri, Voc= 420 mV, Isc=10 mA’dir. En iyi ışık şiddeti  4000 lüx ve buna karşılık gelen Metal-GS-DHP elektriksel pil parametreleri, Voc= 540 mV Isc=18 mA’dir. Deney sonuçlarından anlaşılacağı üzere Metal-GS-DHP elektriksel pil parametreleri anodizasyon koşullarına direk bağlıdır.

No abstract

31CrMoV9 and 34CrAlMo5 are high-performance steels used in many industrial applications in which machines and components are exposed to high surface stresses and dynamic loads. Depending on the customer needs, these steels are first machined on CNC machines and then their surfaces are hardened by nitriding. After nitriding, grinding is needed to reduce the surface roughness values of the product according to the customer demand or the need of the production. Grinding is a chip removal process that uses an a grinding wheel as the cutting tool. However, one of the major drawback for grinding process is significant amount of processing costs. For some applications, such as pump drive shaft, it is foreseen that elimination of grinding step in workflow may reduce significantly cost item for the manufacturer. In this study, the machining parameters of hydraulic pump drive shafts produced from 31CrMoV9 and 34CrAlMo5 materials were changed before nitriding process and after nitriding no grinding process was applied and surface roughness after heat treatment was measured. In the final machining process, 54 hydraulic pump drive shaft samples made of both 31CrMoV9 and 34CrAlMo5 steel material were processed and the cutting edge moving value was used as a variable parameter. Thus, it was investigated whether it is possible to remove the grinding step after nitriding. According to the measurement results, it was observed that the surface roughness of the pump shafts made of both steel materials was negatively affected after the heat treatment, but this change was limited by changing the turning conditions. Finally, by removing the grinding process from the production process, it is aimed to shorten the total production time of the products and reduce the production cost.

No abstract