PM Parts Research Articles

The improvement of dry sliding tribological properties by designing nano-primary cementite in bainitic/martensitic matrix microstructure in hypereutectoid PM components

The production of nano-sized primary cementite in bainite/martensite matrix (NCBM) microstructure was designed to improve the dry sliding wear properties of high carbon PM parts. A different heat treatment cycle was carried out for the production of novel the NCBM microstructure. High purity iron powder 1.5 wt%. natural graphite powder was added and it was compacted in the form of a dry sliding wear test specimen in a mold and sintered at 1200 °C in a pure Ar gas atmosphere. The novel NCBM microstructure in the PM material was produced by quenching at 950 °C, then annealing at 600 °C for 12 min, then quickly cooling from 730 °C to 250 °C in a salt bath and keeping it isothermal for 100 s. The friction coefficient of materials with NCBM microstructure was less than other samples. It was found that while the wear coefficient were higher in the tempered martensitic microstructure sample having higher hardness, they were less than in the sample having bainitic/martensitic microstructure with similar hardness.

Assessment of Two Advanced Aluminium-Based Metal Matrix Composites for Application to High Energy Physics Detectors

The Outer Tracker of the Compact Muon Solenoid (CMS), one of the large experiments at the CERN Large Hadron Collider, will consist of about 13,200 modules, each built up of two silicon sensors. The modules and support structures include thousands of parts that contribute to positioning and cooling the sensors during operation at -30 °C. These parts should be low mass while featuring high thermal conductivity, stiffness and strength. Their thermal expansion coefficient should match that of silicon to avoid deformations during cooling cycles. Due to their unique thermal and mechanical properties, aluminium-carbon fibre (Al/Cf) Metal Matrix Composites are the material of choice to produce such light and stable thermal management components for High Energy Physics detectors. For the CMS Outer Tracker, about 500,000 cm3 of Al/Cf raw material will be required to be produced through a reliable process to guarantee consistent properties throughout parts manufacturing. Two Al/Cf production routes are currently considered: liquid casting by gas-pressure infiltration and a powder metallurgy process based on continuous semi-liquid phase sintering. The dimensional stability of the resulting material is of paramount importance. Irreversible change of shape may be induced by moisture adsorption and the onset of galvanic corrosion at the discontinuous interfaces between Cf and Al. This paper presents the results of an extensive investigation through Computed Microtomography, direct microscopical investigations, analysis of the interfaces and metrology measurements aimed at comparing and interpreting the response to different environments of the respective products. The results obtained confirm the suitability of the two investigated Al/Cf MMCs for application to components of the CMS Outer Tracker, requiring tight geometrical control and microstructural stability over time. However, for PM parts sintered through the semi-liquid phase process, a multilayered protective noble metal coating is necessary the make them impervious to moisture, allowing dimensional stability to be guaranteed and the onset of corrosion phenomena to be avoided, while the product obtained by gas-pressure infiltration has shown less sensitive even to extreme temperature-humidity cycles and may be used uncoated.

PM parts and manufacturing technologies leading to SDGs

PM parts and manufacturing technologies leading to SDGs

The Masteralloy Concept for Sintered Steels - New Impetus for a Classical Approach

Among the various alloying techniques used in powder metallurgy, the masteralloy concept has been known for a long time. However, its use for production of ferrous precision parts has been hampered by several obstacles such as poor output of the useful fine fractions, high tool wear and slow homogenization kinetics of the alloy elements in the matrix. On the other hand, the masteralloy concept is particularly interesting for introducing cost-effective alloy elements such as Cr, Mn and Si since the masteralloy approach at least alleviates the problems caused by the high oxygen affinity of these elements. In the present study it is shown that recent developments have given a boost to this classical concept, one of these developments being powder manufacturing by high pressure water atomization which dramatically increases the yield of fine masteralloy fractions. The other progress is availability of thermodynamic software that enables defining masteralloy compositions with low melting range and thus fast homogenization also at moderate sintering temperatures. Combined, these new developments open the door for implementation of the masteralloy route in large scale PM parts production.

Development and Practical Application of Innovative Compacting Technology for Automotive PM Parts

Development and Practical Application of Innovative Compacting Technology for Automotive PM Parts

Recent Topics in Evaluation Technologies of PM Parts

Recent Topics in Evaluation Technologies of PM Parts

The Key Technologies of PM Parts for the Next Car Generation

The Key Technologies of PM Parts for the Next Car Generation

Perspectives of Powder Metallurgy in the 2020s

In the automotive industry there is a clear trend towards alternative drivetrain systems, away from the classical internal combustion – gasoline or diesel - engines. This poses a challenge to the traditional markets of powder metallurgy, the ferrous precision parts for automotive engines and transmissions which form the major tonnage of today’s powder metallurgy [1, 2], but also the hardmetal tools for machining automotive components from stock material or for finishing [3]. To counter these trends, powder metallurgy can rely on its high flexibility regarding materials, geometries, processing and properties and finally applications, which enables PM to adapt itself to changing requirements in a changing industrial environment [4]. In the present article, examples are given both for PM precision parts and hardmetals but also functional materials such as soft magnetic composites. It is shown that the potential of ferrous PM parts regarding mechanical performance is still higher than currently used, high and graded density being attractive ways [5]. Also the use of advanced alloying systems offers economical and technical advantages and should enable PM to enter non-automotive markets for precision parts. In the hardmetal branch, non-automotive applications, e.g. in construction and mining, should be considered while from the material viewpoint replacing tungsten and in particular Co as binder metal are intensely studied. PM functional materials such as Fe-Ni, Fe-Co and in particular soft magnetic composites will find markets in electrical drive systems [6], enabling new designs for electric motors. On the other end of the spectrum, superhard rare earth magnets are regularly produced by the powder route. Finally, the multitude of additive manufacturing techniques offers chances for powder metallurgy since most of these processes start from metal powders [7]. In addition to the well known laser and electron beam based “direct” AM systems, also indirect, binder-based, variants are attractive, avoiding many problems encountered with the direct systems and enabling transfer of knowhow accumulated in metal injection moulding. In general, future will show how many other technologies and products has to offer in addition to the classical press-and-sinter routes which however will remain for their specific product groups. when designing your figures and tables, etc

Novel multiuse liquid phase promoter for PM components

AbstractThe aim of this work was to characterize the behavior of a novel multiuse B‐free alloy that was designed as a liquid phase promoter and as a filler material for sintering and brazing steels in N2‐H2. Through thermodynamic calculations, a new Cu‐Fe‐Ni‐Si alloy (named LP) has been designed showing a proper melting point suitable for being used at temperatures below 1100°C, with good wetting behavior that allows it use as brazing material and liquid phase former. This new boron‐free alloy has shown good dimensional behavior, good brazeability, and competitive mechanical properties. These demonstrated features allow the developed alloy it use as braze material for PM parts in industrial furnaces as well as master alloy to promote transient liquid phase in PM structural steels.

Investigation of Microstructure and Wear Properties of Plasma Nitrided Astaloy Mo

In this research, plasma nitridation is carried out on the as-sintered and hardened Astaloy Mo in order to improve the wear behavior of PM parts. The starting materials including pre-alloyed powders with 0.8% graphite were pressed at different pressures. Next, the specimens were sintered at 1120 °C for 30 min, in the N2/H2 atmosphere. The effects of density and cooling rate were studied on the microhardness, microstructure, and wear performance of as-sintered and hardened specimens. X-ray technique, scanning electron microscopy, and energy dispersive spectroscopy were used for phase transformation, morphology characterization, and elemental analysis, respectively. The results showed that plasma nitridation and an increase in cooling rate and density up to 6.8 g/cm3 resulted in a change in wear resistance. Moreover, the wear performance of dense samples was decreased due to the enhanced three-body abrasive mechanism.

What Will Be the Future of Powder Metallurgy?

Abstract Traditionally, powder metallurgy has been based on two major industrial sectors – ferrous precision parts and hardmetals. Both of them relied heavily on the automotive industry, with focus on internal combustion engines. Today, there is an increasing trend towards alternative drivetrain systems, and powder metallurgy faces the challenge to find new applications to replace those lost with the decrease of classical internal combustion drives. In this presentation it is shown that the main strength of powder metallurgy lies in its enormous flexibility regarding materials, geometries, processing and properties. This enables PM to adapt itself to changing requirements in a changing industrial environment. Examples given are PM parts in alternative drivetrain systems, new alloying concepts and processing routes offering distinct advantages. With hardmetals, innovative microstructures as well as sophisticated coatings offer increased lifetime, applications ranging from metalworking to rockdrilling and concrete cutting. A particularly wide area is found in functional materials which range from components for high power switches to such for fuel cells. Soft and hard magnets are accessible by PM with particularly good properties, PM having in part exclusivity in that respect, such as for NdFeB superhard magnets as well as soft magnetic composites (SMCs). Metal injection moulding (MIM) is gaining further ground, e.g. in the medical area which is a fast-growing field, due to demographic effects. Finally, most additive manufacturing techniques are powder based, and here, the knowledge in powder handling and processing available in the PM community is essential for obtaining stable processes and reliable products. Conclusively it can be stated that PM is on the way to fully exploit its potential far beyond its traditional areas of applications.

Higher density, higher performance at POWDERMET2018

Achievements and opportunities for obtaining high strength in ferrous PM parts were reviewed in two separate programs at POWDERMET2018 in San Antonio. Presentations covered advances from powders to compacting, sintering and hardening.

Heat Treatment of Sintered Steels – what is different?*

Abstract Powder metallurgy ferrous precision parts are employed in numerous industrial sectors. In case of high mechanical loading, as e. g. in automotive applications, heat treatment is frequently required after the press-and-sinter manufacturing. Here the specific features of PM parts have to be considered, in particular the presence of open and/or graded porosity. In the present study it is shown that processes such as sinter hardening, low pressure carburizing and plasma nitriding are particularly suited for sintered parts since the problems usually caused by the porosity can largely be avoided. By appropriate selection of the alloying system combined with optimum sintering and heat treatment, components can be obtained that are competitive to parts machined from wrought steels but offer additional benefits such as attractive NVH (noise-vibration-harshness) behavior.

Optimization of Low Pressure Carburizing and High Pressure Gas Quenching for Cr-alloyed PM parts*

Abstract Today Low Pressure Carburizing (LPC) followed by High Pressure Gas Quenching (HPGQ) is an established process to produce high performance components for conventional steels in order to combine high surface hardness and fatigue strength. On the other hand, thanks to its ability to combine good quality and cost saving, PM process is more and more popular in the automotive industry (especially in the transmission applications as synchronizer hubs/rings, sliding sleeves, …). In order to answer the increasing application performance requirements, chromium-alloyed grades are often used because they provide a cost-efficient way to reach high mechanical properties. However these materials need specific sintering conditions and cannot be surface hardened by conventional gas carburization and oil quenching. Thus, the alternative LPC & HPGQ applied to PM parts is a very promising, cost-efficient, and environmental solution to produce high performance parts. This paper presents the last trends and results of this solution.

Heat treatment of PM parts by Hot Isostatic Pressing

Hot Isostatic Pressing (HIP) is a technology that has been around for 60+ years. By using high temperature and high gas pressure, dry metal and ceramic powders can be consolidated and a volume decrease can be achieved. Later developments include rapid cooling and rapid quenching to enable higher productivity and high-pressure heat treatment. This paper shows the advantages of having HIPing and Heat Treatment combined for Powder metallurgy parts.

ANCORBRAZE 72

Abstract Ancorbraze 72 is a sinterbraze material to join ferrous PM parts to each other or ferrous PM parts to wrought substrates. This datasheet provides information on composition, physical properties, and compressive strength. It also includes information on powder metal forms. Filing Code: Ni-741. Producer or source: Hoeganaes Corporation.

PM personality: James P. Adams, MPIF Executive Director/CEO

Newly appointed Executive Director/CEO of MPIF, Jim Adams, sat down with MPR's consulting editor Joseph Capus during the MIM2017 Conference in Orlando, Florida. Adams explained that he had no knowledge of the PM industry until a school visit to the Hennepin Technical Center inspired him to make a career in the industry. He joined the staff of MPIF in 2004 after spending nearly 20 years in PM parts manufacturing and powder production companies, and today is the first Executive Director/CEO of MPIF to have had first-hand experience of PM. He sees an extremely exciting future for the industry.

高性能銅系焼結部品用原料粉末の開発

高性能銅系焼結部品用原料粉末の開発

ELASTIC PROPERTIES AND STRUCTURAL OBSERVATIONS OF DISTALOY SA POWDER SINTERED WITH BORON AND CARBON

One of the methods aimed at increasing the density in PM parts is the process of activated sintering performed by adding boron as elementary boron powder, for example. Under this researchwork novel, PM materials were obtained based on prealloyed and diffusion bonded powder (type: Distaloy SA) with the following chemical composition: Fe-1.75%Ni-1.5%Cu-0.5%Mo, with the addition of 0.55 wt.% carbon and boron (0.2, 0.4 and 0.6 wt.%). Distaloy SA samples alloyed with carbon and boron were manufactured by mixing the powders in a Turbula mixer, then compacting the mixture in a hydraulic press under a pressure of 600 MPa and sintered in a tube furnace at 1473 K for 60 minutes in a hydrogen atmosphere. The densification process of Distaloy SA parts with boron and carbon depends on the sintering mechanism. In order to evaluate the sintering mechanism of the PM samples, structural investigations using SEM/EDS were performed. During sintering of these materials at 1473 K, a liquid phase is generated as a result of the reaction occurring between the alloy matrix and the complex of carbo-borides, which leads to a considerable degree of consolidation. The elastic properties of the sintered samples (such as Young’s modulus and the damping coefficient) were measured in a tensile test with a Forster elastometer.

US manufacturers in forefront at 2016 PM Design Competition

Reversing a recent trend, US fabricators of PM and MIM parts made an impressive showing at this year's MPIF Design Excellence Awards Competition.