In this study, the effect of oxygen addition on the microstructures of Ti-18%Mo-10%Cr alloy was investigated. The alloy was fabricated by a powder metallurgy method. The samples were subjected to sintering at 1300°C for 4 hours and furnace cooling. A Bo-Md method was initially applied for predicting stable phase. Calculation using the Bo-Md method showed that Ti-18%Mo-10%Cr alloy have bcc (β) phase at ambient temperature. All samples with various oxygen contents exhibited needle-like structures within equiaxed grains. The increase of oxygen content promoted formation of porosity in the α phase. Calculation of phase stability using JMatProTM showed that the decrease of β phase’s stability was not due to formation of the α phase on sintering, but due to promotion of nucleation and grain growth of diffusional α phase upon furnace cooling. It was also shown that vol.% of porosity of the alloy slightly increased with increasing oxygen content. Therefore, the increase of oxygen concentration could accelerate the formation of α phase and reduce the alloy’s density. The hardness increased as the oxygen concentration increased. The increase of the hardness might be due to combination of the solid solution hardening of oxygen and the precipitation hardening of α phase.
This study aimed to investigate the effects of element diffusion on the alloying behaviour and microstructure of a Ti-10%Mo-10%Cr alloy during sintering and furnace cooling. A theoretical calculation of the average diffusion distance for each element was performed to predict the alloying behaviour during sintering and furnace cooling. The Ti-10%Mo-10%Cr alloy was fabricated using a blended element powder metallurgy approach. Micrograph of the samples after sintering showed bright-circle structures and significantly decreased equiaxed structures. The number of plate-like structures increased with prolonged sintering time. Microstructural changes occurred because of element diffusion resulting from the prolonged sintering time. Moreover, the diffusion distance of each element also increased with prolonged sintering time. Although elements can sufficiently diffuse during both sintering and furnace cooling, the diffusion distance during sintering was considerably higher than that during furnace cooling for all elements. The diffusion distances of Cr and Mo were the highest and lowest, respectively, during sintering and furnace cooling. This study showed that alloying behaviour mostly occurred during sintering and was controlled by the diffusion of Mo atoms.
Planting of oil palm in peatland has been limited by soil physical, chemical properties, and hydrology, that`s way needed improvement on those matters to increase the productivity of peat and oil palm in peat soil by compacting. The purpose of this compacting is to improve the soil's physical, chemical properties, and soil moisture. A sampling of soil, water, and leaf were done in consecutive block 5,4,3,2,1,0 year after compacting and of planting done 4 years 10 months, 3 years 9 months, 2 years 9 months, 1 year 10 months, 11 months and 2 months, control used in this trial are origin condition (forest). Increasing bulk density was found at compacting block with 30 cm depth from the surface with the lower in 2 years after compacting at 0.09 g/cm3 and highest 4 years after compacting 0.4 g/cm3. In-depth of 60 cm from surface was found no increasing the bulk density 3 years after compacting 0.0 g/cm3 and the highest on 5 years after compacting 0.3 g/cm3 compared to forest. Decreasing on permeability in-depth 30 cm at 4 years after compacting 7.47 cm/jam and close to forest permeability 51.11 cm/hour is 2 years 43.6 cm/hour. As represent rise capillary consistently water content ≥ 80% achieved at depth 20 cm of surfaces on all block. Compaction doesn't regard pH, C organic, basa's saturation, capacity exchange cation. On depth 30 cm P-total lower on s without compaction at 599.6 ppm and above 871.6 ppm on 5 yr than forest 585 ppm. P available most low 58.1 ppm happens on 4 yr afters is compacted and p available forest 53.9 ppm. Nutrient content B, Cu and Zn at soil not influenced by compaction. Fosfor (P) in water increases with added years after compaction lower at 39.1 mg/L in the block without compaction compare of forest that 40.8 mg/L. Leaf nutrient rate on compacted block on optimum until excess where N (2. 69 – 3.15 %) , P (0. 170 – 0.209 %) , K( 0. 952 – 1.11%) , Mg ( 0. 377 – 0.497%) , except on block without compacting K (0. 830 %) and Mg (0. 190%) at deficiency and 0 years afters compaction Mg leaf on level deficiency 0. 230%. Nutrient content of B, Cu and Zn at various level and not influenced by compacting.
Titanium and its alloys have been widely used in automotive industry due to their high specific strength, excellent corrosion resistance, high temperature capability and low density. In this study, the microstructural changes of Ti-10at%Mo-10at%Cr alloy on sintering process was observed to clarify alloying behavior. The sample was fabricated using powder metallurgy process with two main operations on sintering process, ie sintering in a vacuum condition at temperatures of 1573K and furnace cooling with. Microstructures were observed by optical microscopy and scanning electron microscopy (SEM). The distribution of elements in the sample was analyzed using SEM - energy-dispersive X-ray spectroscopy (EDS). Micrograph of the samples after sintering process shows the microstructure of bright-circle structures, equiaxed structures, plate-like structures and pores. Composition of microstructures changed with the prolonging of sintering time. The microstructural change was due to diffusion of composing elements on sintering. The bright-circle and the equiaxed structure significantly decreased, while the plate-like structure increased, as sintering time increased. Moreover, the volume fraction of the pores slightly increased. On the other hand, mechanical properties of the sample, namely hardness was increased. This observations revealed that the sintering, which promotes the diffusion of alloying elements, have a significant influence on the microstructural changes.
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