Features of structure formation in sintered Ti2AlNb-based alloy produced by cold compaction and pressureless sintering

The possibility of obtaining a high-density Ti2AlNb-based alloy by cold compaction and pressureless sintering of rapidly solidified fibers of the alloy is studied in the initial state of fibers and after hydrogenation and milling. The possibilities of obtaining high-density sintered materials with lower oxygen content are analyzed.

Next generation powder compaction process

Powder Compaction Process (PCP) is a production method commonly used in the manufacturing industry today. Several analysis methods for powder compaction process are developed and being used in order to minimize costly experiments, to produce complicated near-net shape and to optimize serial production of details. This thesis has dealt with Finite Element (FE) simulation of the cold compaction process. The reason for simulating cold compaction is to predict relative density distribution in the compact for various powder fill and punch motion options. An evaluation of a number of commercial FE codes has been carried out. The MSC Marc program, which incorporates the Shima Model, has been used for compaction of Fe-based metal powders. The relative density distributions of the pressure models and the displacement models of the cylindrical and the stepped cylindrical geometries obtained via FE simulation in this research are encouraging that agree well with observations made in practice.

Next generation powder compaction process

Powder Compaction Process (PCP) is a production method commonly used in the manufacturing industry today. Several analysis methods for powder compaction process are developed and being used in order to minimize costly experiments, to produce complicated near-net shape and to optimize serial production of details. This thesis has dealt with Finite Element (FE) simulation of the cold compaction process. The reason for simulating cold compaction is to predict relative density distribution in the compact for various powder fill and punch motion options. An evaluation of a number of commercial FE codes has been carried out. The MSC Marc program, which incorporates the Shima Model, has been used for compaction of Fe-based metal powders. The relative density distributions of the pressure models and the displacement models of the cylindrical and the stepped cylindrical geometries obtained via FE simulation in this research are encouraging that agree well with observations made in practice.

Comprehensive studies on hot compaction and vibration assisted compaction tests of aluminum powder

Aluminum powder compaction was studied using both test and simulation. Cold compaction, hot compaction and vibration assisted (cold) compaction tests were conducted to achieve different density ratios. Firstly, hot compaction test (at 300°C, compression pressure 140MPa) improved about 6% compared with cold compaction under the same compression pressure. Secondly, although the relative density ratio doesn’t obviously improve at vibration assisted (cold) compaction, the strength of the specimens made under vibration loading is much better than those of cold compaction. Additionally, finite element models with well calibrated Drucker Prager Cap (DPC) material constitutive model were built in Abaqus/standard to simulate the powder compaction process. The results of finite element model have very good correlations with test results up to the tested range, and this finite element model further predicts the loading conditions needed to achieve the higher density ratios. Two exponential equations of the predicted density ratio were obtained by combining the test data and the simulation results. A new analytical solution was developed to predict the axial pressure versus the density ratio for the powder compaction according to DPC material model. The results between the analytical solution and the simulation model have a very good match.

Study on the properties of Permanent Cold Patching (PCP)

Patching road pothole can be done using Permanent Cold Patching (PCP). This research main aim was to analyze the characteristic of the PCP. PCP Super Cold Mix Asphalt was used for the experiment. The mixtures were compacted Marshall hummer in lab using, and plate compactor on site. It was obtained that: compaction temperature variation significantly affected the characteristic of the mixture. Compaction at 100°C and 150°C, met stability, porosity and VMA specification, but not for the VFB. It required more compaction energy. The stability of cold compacted mixture at the age of 1 hour gave 844.74 kg (min. 500 kg). Towards this value, at the age of 48 hours; 96 hours; 192 hours; 384 hours, respectively gave increase of stability of 102%; 140%; 183%; 187% and then constant. Cold compaction on site gave less performance with porosity values in a range of 4.585-8.22% (spec. 4% -10%), therefore the VFB is less than minimum 65% of VMA; the stability obtained was 1422.72 kg (>min 500kg) or 58% stability of the samples compacted in lab at the same 16 days of age where stability had become maximum (constant). Cantabro test result of the cold mix gave 100% weight loss (the sample disintegrated), meanwhile the hot mix only lost 7.56% from 16% max loss.