Study of the Possibilities of Obtaining Powder Materials by Rotational Turning with Multi-Faceted Cutters

Composite materials obtained through powder metallurgy methods are increasingly applied in various industries, particularly in aviation and rocket and space equipment which use their high specific strength, resistance to high temperatures and other properties. Producers of composite materials use various metallic and non-metallic materials (fibres and powders) as fillers [1-2]. For example, the high plasticity (moldability) of aluminium powders allows utilizing them as a matrix material in moulding of composites using various methods of rolling, extrusion, and intense plastic deformation [3-5]. However, the widespread use of chip as a raw material for the production of composites is hampered by the complexities in obtaining powders with granules of the necessary shape and size.

Features of phase transformations in powder steels upon heating

At present, powder materials are used in practically all branches of industry, from medicine to aerospace technology. This is a wide range of materials ranging from constructional and instrumental materials and ending with special-purpose materials and medical implants. Powder metallurgy methods are most often used where the manufacture of products with desired properties is impossible using traditional methods: casting, stamping, etc. Heat treatment is understood as a set of operations of heating, holding at high temperatures and cooling in order to change the structure and workability of the material, improve the combination of its mechanical and physical properties without changing the shape and size of products. Heat treatment is an effective method for improving the physical and mechanical properties and wear resistance of steel. The specific features of sintered steels (porosity, structural heterogeneity, high oxidizability, etc.) make it difficult to use the technological modes of heat treatment developed for cast steels, although the main regularities of the processes occurring during heating and cooling of compact steel can be transferred to sintered materials. Heat treatment of powder steels has a number of features, primarily due to residual porosity, as well as chemical and structural heterogeneity.

SPS Temperature Influence on the Composition, Structure and Magnetic Properties of Hematite Ceramics

Spark Plasma Sintering (SPS), also known as pulsed electric current sintering (PECS) or field assisted sintering technology (FAST), belongs to a class of powder metallurgy methods. Investigations of the effect of thermal, electric and electromagnetic fields arising under the conditions of spark plasma sintering of ceramic materials on their final characteristics are of important fundamental scientific significance. In this regard, the work investigated the effect of the IPA temperature on the structure, composition and magnetic properties of hematite α-Fe2O3 of high purity 99.995%. Changes in the structure and composition of ceramic specimens under SPS conditions in the temperature range 800-1000°C are described by scanning electron microscopy and X-ray phase analysis. The magnetic properties are studied and the regularities of changes of the magnetization (Ms) and coercive force (Hc) under the influence of an external magnetic field for ceramic samples are determined depending on the temperature of the SPS. These results can be considered as initial study of the process of consolidation of materials with weak ferromagnetism under conditions of spark plasma sintering.

Tribiological behavior of modified phenolic resin composites for braking applications

Purpose The purpose of this paper is to investigate the influence of binder effect on tribological behavior of brake friction composite materials: a case study of phenolic resin modified by N-Methylaniline. Design/methodology/approach Four different friction materials have been fabricated by varying modified phenolic resin content. The samples were prepared by the conventional powder metallurgy methods following ball milling, mixing, pre-forming, hot pressing and post-curing processes. Thermogravimetric analysis was used to determination of the degradation mechanism of organic components and study of thermal stability of the samples. A friction test was carried out in dry conditions using a vertical tribometer. Analysis of worn surfaces was performed using a scanning electron microscope. Findings The experimental results revealed that the sample containing 25 Wt.% phenolic resin has good mechanical and thermal properties with stable friction characteristics. Originality/value This paper presents the effect of N-methylaniline modified phenolic resin on friction composites to improve tribological performance by its thermal properties.

MODELING THE HARDNESS AND POROSITY OF BRAKE PAD MATERIALS

In this study, experiment were conducted to determine influental process parameters to the hardness and porosity properties of newly developed brake pad composites. Brake pad composites were preperad by traditional powder metallurgy methods. The development of friction brake pad specimens used in this work were based on a non-asbestos organic type formulation. The plan of experiments conducted to by 2-level design model using 5 factor on base L8 array. Results of analysis of variance showed that “plasticizer” was most important factor to influence both properties. Keywords: friction composites, hardness, porosity, powder metallurgy, Taguchi’s technique

TECHNOLOGICAL WAYS TO CREATE COMPOSITE MATERIALS BASED ON HEAT-RESISTANT REFRACTORY COMPOUNDS (review)

The article discusses the main technological approaches to obtain heat-resistant and heat-resistant materials based on compounds in the Ni–Al system in order to use them in promising products of aviation and rocket technology. It is shown that when receiving materials based on compounds in the Ni-Al system, a phase of eutectic origin is formed based on the Ni3Al compound, which reduces the technological plasticity of the alloys of this system. The use of powder metallurgy methods eliminates such phases in the structure of alloys obtained using granule metallurgy technology, as well as with the use of special methods of powder metallurgy. Technological approaches are presented to obtain similar materials using powder metallurgy methods combined with thermomechanical processing.

The method of calculation of the deviation of the tool axis when machining small diameter holes

The article is devoted to an important parameter that characterizes the accuracy of the shape and location of the hole after machining — the displacement of the hole axis. When designing operations for drilling small-diameter holes with a large depth (the ratio of the hole depth to its diameter is more than 10), a method for predicting this parameter is necessary to improve the accuracy of work. The article considers the causes and methods of eliminating this negative impact on hole machining using the example of a small-diameter drill axis runout. Recommendations are given for reducing drill runout: to reduce cutting modes; to perform the drilling operation while rotating the workpiece, which can stabilize the drill position during machining; to use drills made of hard alloy or obtained by powder metallurgy methods, which increases their rigidity; before drilling the workpiece, to center the hole with a more rigid drill.

Systematic Review of Powder Metallurgy: Current Overview of Manufactured Materials and Challenges for Future Research

The journey toward foundry and the increasing implementation of Powder Metallurgy are evoking replacing traditional Sand Casting, thus, creating new challenges and opportunities. To take advantage of these opportunities and deal with the challenges, we must gain a holistic understanding of the emerging technical interactions and apply new approaches and methods when introducing new technologies and designing Powder Metallurgy. In this paper, we present the findings of a systematic literature review, consisting of quantitative and qualitative data, focusing on investigating Powder Metallurgy, as an alternative to traditional Sand Casting, by comparing certain characteristics of either process to synthesize the existing information of each method and to present an overview of manufactured materials. Although results indicate an increasing current trend in research publications, showing Powder Metallurgy with many advantages over traditional casting, the latter continues to be implemented as the preferred option in industries with low-level casting production. Given that the studies indicate greater advances in Powder Metallurgy methods over traditional casting, we identified the need for more research on the former under different contexts and therefore recommend it as an approach for future studies of metal casting. This review both reorganizes the available knowledge on Powder Metallurgy, as well as it makes an important methodological contribution by applying a review in Materials science, where there is little to no systematic research, which often means failure to provide sufficient help to implement Powder Metallurgy. Based on these findings, we point to future research needs, highlighting the need for further empirical evidence and improved collaboration between the topics of Mechanical Engineering, Manufacturing Processes, and Materials science, as well as with practitioners.