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There is a problem in obtaining a suitable impact strength of the padding weld after cladding with a martensitic filler metal. Too low annealing temperature below 580°C and the excessive annealing temperature above 650°C do not provide adequate impact strength of the padding weld. A heat treatment technology for mixed joints has been developed based on the results of the microscopic observations, X-ray diffraction measurements and transmission electron microscope examination. The problem was identified and a special technology of heat treatment for the dissimilar joint was elaborated. This technology provides a high impact resistance of the padding weld and an appropriate properties of the base material.

The paper presents the results of the investigation of microstructure of the welded X5CrNiCuNb16-4 (17-4PH) steel after solution treatment and aging at 620°C for different periods. The microstructure and the phase composition of the steel was investigated using light microscopy (LM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM) and the X-ray diffraction (XRD). Hardness was measured for samples aged at different times. Density distributions of Cu precipitates were established. The investigation has shown that the microstructure of the X5CrNiCuNb16-4 steel welds after aging at 620 ° C consists of tempered martensite, fine Cu precipitates and austenite. It was observed that the size of the Cu precipitates increases with increasing the aging time, what affects the decrease of hardness. Simultaneously, the quantity of reversed austenite increases with increase of aging time. It was revealed that enrichment of the austenite in Ni, Cu and C affects the increase of Ms, but this factor does not determine the stability of austenite.

Nickel-based refractory alloys are used in the aerospace industry as materials for the production of engine turbine blades obtained by the casting method. Both casting process and surface quality of the ceramic mould have a significant influence on product properties. Current research involved the investigation of interactions between oxide ceramics, forming the basic material of casting moulds and crystallisers, and Inconel 713C nickel superalloy. The wettability of ceramics by Inconel 713C was tested for the three types of materials at temperatures commonly used in the directional casting of this alloy. The oxide ceramics/Inconel 713C interfaces were examined by SEM to reveal the microstructure of phase boundary and assess the degree of degradation of the casting mould ceramic coating.

Crystalline-amorphous matrix composites preserve the amorphous material high strength and additionally gains on plasticity. Substituting hard crystalline precipitates with soft ones should even more improve the latter. Therefore, this work was aimed at verifying, whether Ag and Ni-Si-B alloy shows liquid immiscibility and consequently, if they might form crystalline Ag/Ni-Si-B amorphous/crystalline composite. Firstly, a mixture of 95 wt% of Ni-Si-B (1559-40) and 5 wt% of Ag powders was arc-melted in argon and cooled at copper plate. The solidification process was documented by IR mid-wave camera and Time/Temperature graph. The microstructure of the ingot was studied using a scanning electron microscope (SEM) and light microscope (LM). Secondly, the powders mixture was plasma sprayed on a cooled copper plate. The cross-section microstructure and the phase composition of the plasma spray deposit were analyzed with a transmission electron microscope (TEM), scanning electron microscope (SEM) and X-ray diffractometer (XRD). The thermal characteristics of the plasma sprayed deposit and the Ni-Si-B powder were analyzed using differential thermal analysis (DTA) and compared. The results show that the melted Ag and Ni-Si-B powders form immiscible liquids at high temperatures used both during arc-melting and plasma-spraying. The proved that that the plasma spraying enables production of a Ni-Si-B/Ag composite with high strength Ni-based matrix with dispersed in it fine soft Ag-FCC flake-like particles.

The paper presents research results of the influence of heat input into high carbon rail steel during cutting processes on microstructure transformation and cracking. The massive block of steel prepared for rail rolling processes was cut and examined by nondestructive magnetic testing and destructive testing by microscopic examination and hardness measurements. The results show unfavorable microstructure changes where pearlite and transformed ledeburite were obtained. The effects of the presence of such microstructures are high hardness near to cutting surfaces (above 800 HV) and microcracks which grow into low hardness block cores during rolling and rail shaping.

The 17Cr–9Ni–3Mo precipitation hardened (PH) steel was processed after re-melting using different cooling rates including copper plate chilling and the melt-spinning. The effect of different cooling rates and the sub-zero treatment on the microstructure of the 17Cr–9Ni–3Mo steel was studied. The microstructure and the phase composition of the steel was investigated using light microscopy (LM), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS), transmission electron microscopy (TEM), the X-ray diffraction (XRD) and Mossbauer spectroscopy. The results show that the microstructure of 17Cr–9Ni–3Mo steel after rapid solidification consists of austenite and δ-ferrite. The quantity of austenite increases with the increase of cooling rate. Sub-zero treatment of the samples cooled at the rate of 4 × 104 K/s and 2 × 105 K/s reduces the quantity of austenite as a result of austenite → martensite transformation. For the samples cooled at the rate of 2 × 106 K/s the quantity of austenite in the microstructure does not change when compared to the state before and after sub-zero treatment. The model for the formation of microstructures during rapid cooling was proposed.

The aim of the work was to investigate the influence of the processing on the final microstructure and properties of the melt-spun Ni–Fe–Cu–P, Ni–Fe–P and Ni–Cu–P alloys ejected in two ways. In the first case, the alloy was molten in a simple single-chamber crucible, then ejected as uniform liquid. In the second case the double-chamber crucible was used, and the flux composed of the two Ni–Fe–P and Ni–Cu–P liquids was cooled on a copper roller before forming a uniform mixture. The two component melt spinning (TCMS) was performed starting from the Ni40Fe40P20 and Ni70Cu10P20 alloys. Three of the alloys i.e. Ni55Fe20Cu4P20, Ni40Fe40P20 and Ni70Cu10P20 were melt-spun from the traditional single-chamber crucible. The methods applied in this study for microstructural investigations include scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Mossbauer spectroscopy. Thermal stability of the melt-spun alloys was tested using differential scanning calorimetry (DSC). The results of the investigations are described and discussed in terms of the unique features of the TCMS amorphous microstructure. It is shown that this complex phase composition of the amorphous alloy favors formation of the ductile fracture and the multiple shear band formation.

The paper presents results of the mechanical testing and the microstructure analysis of dissimilar welded joint of the R350HT steel and the high-manganese (Hadfield) cast steel using Cr-Ni cast steel spacer. The simulation tests of the welded joint surface deformation were carried out. The macroscopic and microscopic investigation were made using light microscopy (LM) and scanning electron microscopy (SEM). Content of the magnetic phase was measured using magnetoscope. The quantitative metallographic investigation was used for assessment of ferrite and martensite contents and X-ray diffraction phase analysis was carried out. The results showed that during cooling of the spacer after welding, the transformation of metastable austenite into martensite proceeded. In addition to work hardening, the phase transformation of austenite into martensite occurs during the process of the superficial deformation of the spacer while simulated exploitation. This leads to a substantial increase of hardness, and at the same time, causes the increase of wear resistance of the welded joints of crossovers.

The aim of this study is to present the special features and properties of the two alloys of similar average chemical composition Ni55Fe20Cu5P10B10, processed through two different routes. The first alloy was melt-spun after the ejection of homogeneous liquid using a traditional single chamber crucible, and the second alloy was ejected from a double chamber crucible as two separate liquids: i.e., Ni40Fe40B20 and Ni70Cu10P20, mixing only at the orifice area. The studies of the microstructure of the composite alloy were performed through the use of transmission electron microscopy and scanning electron microscopy. The Ni55Fe20Cu5P10B10 two-chamber meltspun (TCMS) alloy, as well as the homogeneous Ni55Fe20Cu5P10B10, Ni40Fe40B20, and Ni70Cu10P20 alloys, were heated to elevated temperatures and their characteristics studied by means of differential scanning calorimetry. The temperature resistivity change method was applied to the examination of the Ni55Fe20Cu5P10B10 TCMS alloy. The phase composition after heat treatment was investigated using X-ray diffraction. The results of the microstructure examination show that the TCMS alloy is an amorphous/amorphous composite, and is notable for its Ni–Fe–B and Ni–Cu–P stripes resulting from its differentiated chemical composition. Another unique feature of the TCMS alloy is that it retains its wood-like morphology even after high-temperature heat treatment. The crystallisation of the TCMS alloy starts from the Ni–Cu–P constituent and ends with the Ni–Fe–B areas of the sample. The results are discussed on the basis of previous work completed on amorphous matrix composites.

The article presents the results of Transvarestraint test of a modern precipitation hardened steel X10CrNiCuNb18-9-3 with copper. For comparison, the results of tests of conventional steel without the addition of copper X5CrNi18-10 are presented. The total length of all cracks and the maximum length of cracks were measured. The study of microstructure (LM, SEM) showed that the austenitic stainless steel X10CrNiCuNb18-9-3 is very prone to hot cracking. After performing the Transvarestraint tests three types of cracks were observed: solidification cracks occurring during crystallization, liquation cracks due to segregation in the heat affected zone (HAZ) and surface cracks. Niobium carbonitrides dispersed in the bands of segregation are the reason of high susceptibility to liquation cracking. Segregation of copper occurring during solidification causes of surface cracking. A combined effect of copper and stresses contributes to formation of hot microcracks. These microcracks propagate to a depth of 20-30 μm.

This work presents a study of the microstructure formed in a liquid immiscible Fe 60 Cu 20 P 10 Si 5 B 5 alloy during moderate cooling on a copper plate and melt-spinning. The alloy ingot was re-melted on a copper plate and observed while cooling using a mid-wave infra-red (MWIR) camera. The heating and cooling characteristics of the melt-spun ribbon were studied using differential scanning calorimetry (DSC). The morphology and chemical composition of the ingot as well as the melt-spun ribbon were analyzed using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The compositions of the ingot and the ribbon were investigated using X-ray diffraction (XRD). Mossbauer spectroscopic measurements showing the influence of adding Cu to the Fe–Si–P–B alloy were also analyzed. The IR images from the MWIR camera enabled direct observation and identification of the liquid state transformations of the alloy. The DSC trace of the melt-spun ribbon showed crystallization of the amorphous matrix and confirmed that high temperature transformations occurred when the alloy was in the liquid state. Observations of the microstructure of the ingot revealed crystalline surface fractal structures formed by the Fe-rich eutectic constituent and Cu-rich fcc spherical precipitates. The morphology of the precipitates indicated that the precipitates formed in the miscibility gap. The microstructure of the melt-spun ribbon is composed of an amorphous Fe-rich matrix and elongated Cu-rich fcc precipitates. The observations based on the study of the microstructure are supported by Mossbauer spectroscopy.

This paper presents the studies of the microstructure and properties of the welded joints made of 15-7Mo precipitation hardened semi-austenitic stainless steel welded by Tungsten Inert Gas. Microstructural changes in the heat treated welded joints was assessed. It was found that the joints of 15-7Mo steel in as welded state contain martensite, austenite and δ-ferrite. Scanning electron microscope study of the joints was carried out. The sub-zero and destabilization heat treatment were found to decrease or completely eliminate the austenite in the microstructure and increase hardness of the welded joint.

Positron annihilation studies of aluminium alloys with nanodispersions of insoluble elements, i.e., In, Sn, Pb and Au were reported. The alloys were obtained using a rapid solidification process. For all alloys, except that with Au, the average diameter of nanoparticles in aluminium matrix was 100 nm, and variance of the size distribution was above 50 nm. Positron annihilation studies reveal the presence of monovacancies or divacancies, which were located at the interface between nanoparticles and the matrix. In the as-cast reference pure aluminium sample as well as the aluminium and gold alloy dislocations were identified as well. The isothermal annealing of the obtained alloys and measurement of the annihilation characteristic, i.e., S-parameter, allow us to determine the activation energy of grain boundary migration, which for the alloys was higher by the factor of four than for the reference sample. The measurements of friction parameters for the alloys confirmed the results reported by the other authors that, the friction coefficient was lower by the factor of about two and the specific wear rate was by the factor of about fifty higher than the reference sample. The present study confirmed the attractive positron affinity of the nanoparticles of In, Sn, Pb and Au compared to aluminium matrix.

article i nfo Metallic glasses; Mossbauer spectroscopy; Scanning electron microscopy (SEM); Transmission electron microscopy (TEM) The purpose of the research is to identify the differences in the final microstructure, fracture and short range order of the Ni55Fe20Cu5P10B10 alloy melt-spun after the ejection of the homogeneous liquid from the standard single chamber crucible and from the crucible with double chamber as the flux of two liquids i.e.: Ni-Fe- Ba nd Ni-Cu-P. The preparation of the alloys involved remelting Ni55Fe20Cu5P10B10 ,N i40Fe40B20 and Ni70Cu10P20 compositions in the arc furnace under titanium gettered argon atmosphere starting from pure metals 99.95 wt.% Ni, 99.95 wt.% Fe, 99.95 wt.% Cu and Ni-B, Fe-B, Ni-P, and Cu-P master alloys. The Ni55Fe20Cu5P10B10 melt-spunribbonswereobtainedbymeansoftwomethods:the firstonewasmelt-spunfromatraditionalsingle chamber crucible while the second one was produced using two component melt spinning (TCMS) performed in the protective helium atmosphere. The research was conducted by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Mossbauer spectroscopy. The results of the microstructure examination show that the TCMS alloy isamorphous/amorphous composite and boundaries between the stripes of the differentiated chemical composition coincide with the features of the ductile fracture. The Mossbauer spectroscopy of the alloys confirms that the special feature of the TCMS alloy is that it is composed of the regions with differentiated chemical composition.

The paper presents rezults of microstructure (LM, TEM) investigation and hardness measurments of welded joints in martensitic precipitation hardened stainless steel containing copper, subjected to heat treatment. For the aging temperature up to 540 °C even for the very long times, the microstructure of the welded joints is similar to this one at lower temerature aging. After aging at 620 °C a distinct change of the microstructure was observed. Non-equilibrium solidification conditions of the weld metal, segregation and the diffusion of copper and the elements stablilizing the austenite cause the occurrence of the reverse transformation of the martensite into austenite as fast as just 1 hour at 620 °C. TEM investigations revealed the differences in dispersion of hardening copper precipitates after aging at temperature 620 °C for 1 and 4 hours.

A nickel–copper–iron–phosphorus Ni 63 Cu 9 Fe 8 P 20 alloy was prepared. The precursors were induction melted in tubes under vacuum (10 −2 bar). The microstructure of the alloy was investigated by use of light microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). Analysis of the morphology was carried out and the volume fraction of microstructural constituents in as-cast state was assessed. The melt spinning was used to produce ribbons from the alloy. The ribbons were then investigated by means of differential thermal analysis (DTA). High temperature X-ray studies of melt-spun ribbons as a function of temperature were carried out in order to characterize thermal stability of the alloy. The results were discussed and compared with other experimental data.

The two-component melt-spun (TCMS) Fe71.25Si9.5B14.25In5 alloy was produced from Fe75Si10B15 and Fe67.5Si9B13.5In10 alloys. The microstructure of the TCMS alloy was investigated by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). A tensile test of the alloy resulted in a tensile strength of Rm = 1040 MPa, yield strength Re = 919 MPa, total plastic elongation etot = 3.29%, and traces of plastic deformation on the surface of the Fe-Si-B-In TCMS sample. Microstructural analysis of the amorphous/crystalline composite and tensile sample free surface show the reason for the ductility of the sample in relation to the Fe75Si10B15 alloy.

Problem of welded joint cracking in the HAZ of Cu strengthened 17-4PH grade precipitation hardening martensitic stainless steel is presented. Hypothesis concerning hydrogen embrittlement origin of the cracks is opposed. It was concluded that the cracks located in the high-temperature zone of the HAZ exhibit characteristics of hot cracks which originated as a result of steel embrittlement in the presence of Cu rich liquid phase. The mechanism of steel surface enrichment in Cu is proposed. Practical methods of cracks elimination are presented.

The aim of the work was to investigate the influence of silver as a modifying constituent on structure formation in Ni-P based glass forming matrix. Nickel-phosphorus-based Ni80P20, Ni78Ag2P20 and Ni76Ag4P20 alloys were prepared from 99.95 wt % Ni, 99.95 wt % Ag, and Ni-P master alloy. The alloys were melt-spun in helium. The microstructure of the melt-spun ribbons was investigated by XRD, a light microscope and a transmission electron microscope. Then the tensile tests were performed. The alloys with silver show lower tensile strength with respect to the fully amorphous Ni80P20 ribbon. The ductility of the amorphous matrix melt-spun Ni78Ag2P20 and Ni76Ag4P20 alloys was improved by addition of silver forming fcc-Ag precipitates in comparison with Ni80P20amorphous alloy. SEM observations of the fracture surfaces show different character of the fractured samples. The pattern and the number of the crack lines changes, depending on the silver content. For the fully amorphous Ni80P20 alloy simple brittle cracks are observed, however the alloys with silver content show more developed surfaces near the fractured regions and form crack lines arranged 60° with loading direction.

This paper reviews the results of investigations on how post-weld heat treatment (PWHT) influences the hardness and microstructures of welded joints in stainless steel X3Cr-NiMo 13-4. It is known that welding leads to high segregation of components in the solidification process, which has an influence on phase transitions in PWHT. The investigated steel has a very narrow PWHT range, about 600–620°C, which provides optimum levels of hardness and toughness. Excessive annealing temperature leads to decreased toughness, which in turn causes exceeding of the Ac1 temperature in the segregation range, which then leads to increased ‘fresh’ martensite content.

Hydrogen's effect on steel properties has already been described in many publications and monographs1,2. Usually in these publications, only hydrogen's effect on properties and cracking at near amb...

This paper shows the results of welding tests used so far on high-temperature creep resistant steels and new bainitic and martensitic steels. The positive results of this research allowed the elaboration of a welding procedure specification that was ultimately approved by TUV. This then allowed the SEFAKO Company to attempt welding of the latest generation boiler steels for use under heavy conditions.

Summary The work presents the microstructure characterization of the new (Fe, Ni)–Cu–(P, Si, B) melt-spun glass forming alloys investigated by means of transmission electron microscope. The results are compared with the data obtained by other complementary methods such as XRD and Mossbauer spectroscopy. The phases occurring during the crystallization of the glassy matrix are identified and characterized in terms of a long-range order and a short-range order. The thermal stability of the alloy is characterized by differential scanning calorimetry. The study describes the mechanical and magnetic properties of the new alloys at room temperature as well as characteristics resulting from heating the as-cast melt-spun alloy at elevated temperatures. The changes of the properties of the alloy at elevated temperatures are correlated with the microstructural changes.

The Cu 68.5 Ni 12 P 19.5 alloy was cast into the ribbons using melt spinning (23 m/s). The amorphous ribbon in the as-cast state was investigated by differential thermal analysis (DTA), dynamic mechanical analysis (DMA), resistivity measurements and X-ray diffraction ‘in situ’ at different temperatures. The work presents attempts to find correlation between the changes of the mechanical properties presented by DMA cycles and during the other tests. The measurements of the relative resistivity R / R 0 versus temperature for repeated heating and cooling cycles to different temperatures show changes of the temperature coefficient of resistivity (TCR) indicating reversible and irreversible transformations in the studied alloy.

Nickel–copper–iron–phosphorus Ni64Cu9Fe8P19 alloy was prepared using 99.95 wt.% Ni, 99.95 wt.% Cu, 99.95 wt.% Fe and the Ni–P master alloy. The precursors were melted in the arc furnace under argon gettered protective atmosphere. Then the alloy was induction melted in quartz tubes under vacuum (10−2 bar) and quenched in water to obtain ingot of 10 mm diameter. The primary microstructure of the ingot was investigated by the use of light microscope. The Ni64Cu9Fe8P19 alloy was cast using melt spinning. The ribbon in the as cast state was characterised with use of transmission electron microscope (TEM) and X-ray diffraction (XRD). Differential thermal analysis (DTA) of the melt-spun ribbon was made to determine the thermal stability and glass forming ability of the alloy. The pieces of ribbon were heated to different temperatures and annealed during 1 h then characterised with use of the Mossbauer spectroscopy and the X-ray diffraction to see the change of the microstructure after heating to elevated temperatures. It has been found that the devitrification sequence consists of progressive formation of the (Ni, Fe, Cu)3P phase and (Ni, Fe, Cu)-FCC phase. The temperature range of the sequence is determined under isochronal conditions.

Quaternary Ni 63 Cu 9 Fe 8 P 20 alloy was prepared using 99.95 wt% Ni, 99.95 wt% Cu, 99.95 wt% Fe and Ni–P master alloy. The precursors were induction melted in quartz tubes under vacuum (10 −2 bar). The microstructure of the alloy was investigated by the use of a light microscope, scanning electron microscope (SEM) with energy dispersive spectroscope (EDS). Analysis of morphology was carried out and volume fraction of microstructural constituents in as-cast state was assessed. Melt spinning was used to produce ribbons from the alloy. The ribbons were then investigated by means of differential scanning calorimetry (DSC) and differential thermal analysis (DTA). High temperature X-ray studies of melt-spun ribbon as a function of temperature were carried in order to characterize thermal stability of the alloy. The results were discussed and compared with other experimental data.

Copper–nickel–phosphorus Cu 68.5 Ni 12 P 19.5 and Cu 66 Ni 11.5 P 22.5 alloys were prepared using 99.95 wt.% Cu, Cu–P and Ni–P master alloys. The precursors were encapsulated in quartz tubes under vacuum (10 −2 bar) and melted in a resistance furnace. Metallographic observations of the alloys were made and volume fraction of microstructural constituents in as-cast state was assessed. The melt spinning was used to produce ribbons from the alloys. The ribbons were then investigated by means of differential scanning calorimetry and differential thermal analysis. High temperature X-ray studies of melt spun ribbons as a function of temperature were carried in order to characterize the thermal stability. The characteristics of the alloys are discussed and compared with other experimental data.