Lamellar Precipitates Research Articles

Effect of Magnesium Modification on Inclusions and Carbide in As‐Cast 21‐4N Valve Steel

To investigate the impact of magnesium on the inclusions, carbides, and microstructure of the 21‐4N valve steel, the magnesium modification industrial experiment is carried out. Optical microscope, a scanning electron microscope with an energy‐dispersive spectrometer, thermodynamic calculation, and a 3D etching method are used. In the results, it is shown that the oxide inclusions in steel modifies from Al2O3–MnO to MgO–MnO–SiO2 after magnesium modification, which presents a more dispersed size distribution. The primary precipitates in the steel remain as massive carbide M23C6 and lamellar precipitate γ + M23C6, and the maximum size of large carbides and lamellar precipitates in the magnesium‐modified steel decreases from 15.1 to 13.4 μm and from 98.8 to 68.8 μm, respectively. Furthermore, Mg‐containing inclusions act as more heterogeneous nucleation cores for austenite precipitation, resulting in the refinement of austenite grain and a reduction in the last‐to‐solidify region. The reduction in the last‐to‐solidify region limits the growth space of carbides and contributes to their size refinement.

Nanocrystallization and precipitation behavior evolution of AZ80 magnesium alloy during multi-directional compression

In response to the growing demand for high-performance magnesium alloys in the aerospace and transportation industries, researchers conducted a study on the AZ80 magnesium alloy. The primary objective was to achieve a nanocrystalline structure in the alloy through severe plastic deformation using low-strain multi-directional compression at room temperature. Subsequently, an aging treatment was performed to induce the transformation of the structure into a stable state. The study aimed to investigate the morphology and mode of the second phase precipitation in the magnesium alloy after undergoing severe plastic deformation. The research findings revealed that the application of multi-directional and multi-pass compression during room temperature deformation of the magnesium alloy effectively prevented instability and fracture. Moreover, this process facilitated the accumulation of larger true strain. As the number of compression passes increased, deformation twins became increasingly denser, particularly in the intersecting areas. Consequently, ultrafine high-angle grain structures were preferentially formed in these regions. Furthermore, the number of fine-grained areas gradually increased with each deformation pass. After ΣΔε 5.12, the grain size was refined to a range of 100–200 nm. Additionally, the aging treatment following severe plastic deformation brought about a significant change in the traditional lamellar precipitation mode of the second phase Mg17Al12 in the magnesium alloy. Instead, spherical precipitation occurred.

Fluorescent Membrane Probes Obey the Israelachvili Rules

AbstractWhen developing fluorescent membrane probes, we naturally tend to focus on the fluorophore itself. In this study, we show that sometimes it can be beneficial to shift attention from the center to the periphery, to maximize multiple interfacing with complex changing environments. Palmitylation for hydrophobic interfacing and glutamate dendrons for hydrophilic interfacing are combined to improve the performance of fluorescent flipper probes. We show that to increase performance in membranes, solubility in water is important, and to increase solubility in water, we increase the hydrophobicity of the flipper probe. These seemingly paradoxical measures are taken to satisfy the Israelachvili rules. They state that only inverted cone amphiphiles form soluble micelles in water, while inverted micelles from cone shaped amphiphiles precipitate into hexagonal 1 supramolecular polymers, and the intermediate cylindrical amphiphiles show intermediate behavior dominated by bilayers and lamellar precipitates. The normal micelles obtained from inverted cone flipper amphiphiles prevent precipitation and prepare for efficient transfer into the lipid bilayer membranes. The results are flippers that break all records set by the 2016 original with regard to effective brightness, responsiveness to membrane order, anchoring in disordered membranes, partitioning into membranes of high order, and stable labeling of membranes of interest. The lessons learned confirm the obvious: The Israelachvili rules apply also to fluorescent membrane probes. They promise literally bright perspectives for fluorescent membrane probes.

Enhanced tensile performance of ternary Fe-Ni-Ti peri-eutectic alloy through directional solidification associated with thermal processing

The microstructural evolution and tensile performance of ternary Fe66.5Ni17.6Ti15.9 peri-eutectic alloy were studied by synergetic modulation of directional solidification and thermal processing technique. The alloy after directional solidification consisted of the vertically growing α-Fe dendrites plus interdendritic γ-Fe(Ni) + Fe2Ti peri-eutectic. The in suit thermal processing promoted the precipitation transition of the α-Fe dendrites, and the lamellar Fe2Ti precipitate was formed along the α-Fe grain boundaries with different orientation relationships. Compared to the conventional solidification, the synergetic modulation not only reduced the transverse grain boundaries and hindered the crack propagation, but also introduced the second phase strengthening and impeded the dislocation movement in the α-Fe dendrites. Eventually, the tensile strength and Young’s modulus of this peri-eutectic alloy were enhanced by 253 % and 72 %.

Discontinuous coarsening leads to unchanged tensile properties in high-entropy alloys with different recrystallization volume fractions

Heterogeneous microstructure alloys provide a possibility for the combination of strength and ductility. As a typical heterogeneous microstructure, partially recrystallized microstructure is attractive because of the convenient processing route and great potential for industrial applications. However, the mechanical properties of this microstructure vary dramatically with different morphology factors, especially the recrystallization fraction, which restricts the processing window and the property consistency. In this study, we found that the yield strength (∼1.3 GPa) and ductility (∼20 %) of the partially recrystallized Ni2CoCrFeTi0.24Al0.2 do not change when the recrystallization fraction increases from 21 % to 72 %. This novel phenomenon is attributed to an additional hetero-deformation induced (HDI) strain hardening effect produced by heterogeneous precipitates. With the increased recrystallization fraction, this additional HDI stress keeps the ductility unchanged by offsetting the decreased HDI stress arising from the hetero-deformation between recrystallized (RX) and non-recrystallized (NRX) areas. The unchanged yield strength comes from the increased strengthening effects of the lamellar precipitates and grain boundaries. We also confirmed that the discontinuous coarsening contributes to the formation of heterogeneous precipitates. These findings would open a new pathway for enhancing the consistency and processability of hetero-structured alloys and thus promote their broader industrial applications.

Tailoring the solidification microstructure and properties of Cu–12Sn-xBi-2Ni alloys by varying Bi content

A novel self-lubricating Cu–12Sn-xBi-2Ni alloy was developed and the effect of Bi on microstructure and properties of Cu–12Sn-xBi-2Ni was investigated. The formation reason of the solidification microstructure was analyzed by CALPHAD method and verified by water quenching experiment. The mechanical properties and the friction properties of alloys were tested by the pin-on-disc wear tester and electronic universal material tester. The tensile property deteriorates with the increase in Bi content, while the Brinell hardness and anti-friction properties of the alloy are enhanced, and Cu–12Sn–6Bi–2Ni alloy is identified to be the alloy with the best self-lubricating property. The addition of Bi increases the number of Sn-rich phase and changes the morphology of Sn-rich phase, resulting in fine Bi-rich phase and lamellar microstructure precipitate around the Sn-rich phase. Liquid Bi as nucleating particles promotes the precipitation of δ phase, resulting in the formation of lamellar δ phase and the Sn-poor α-Cu phase.

High-temperature deformation behaviour and processing map of near eutectic Al–Co–Cr–Fe–Ni alloy

The high-temperature deformation behaviour of near-eutectic high entropy alloy was studied at 800–1100 °C and 0.01–10 s−1. The microstructure of the as-cast alloy depicted a proeutectic L12 phase and epitaxially grown eutectic colonies of lamellar L12 and B2. Deformation temperature and strain rate played vital roles in defining the precipitation and deformation behaviour of the alloy. The lower-temperature deformed samples were characterized by extensive deformation twinning and strain accumulation. In contrast, high-temperature deformation led to uniform deformation with dynamic recrystallization, recovery, B2 lamellar fragmentation and B2 precipitation. The microstructure of the deformed samples corresponded well with the processing maps developed via dynamic materials model. The processing zones for the alloy were identified to be 800–950 °C and 10−2 – 10−1.25 s−1 as well as 925–1100 °C and 10−2 – 10−0.5 s−1. The critical material flow parameters displayed a complex relationship with temperature, strain rate and strain. In the studied temperature and strain rate regime, the critical strain rate was determined to be 0.1s−1. At strain rates above and below this value, the critical strain for recrystallization was higher. Within the studied temperature and strain rate regime, the near eutectic alloy displayed superior compressive strength and wider thermos-mechanical processing region than its eutectic counterpart.

A study of crystallization kinetics, phase formation and magnetic properties of (FeCoNiMn0.25Al0.25)75Si13B12 high-entropy metallic glass

The crystallization kinetics, phase formation and magnetic properties of (FeCoNiMn0.25Al0.25)75Si13B12 high-entropy metallic glass are investigated by thermal analysis, electron microscopic imaging, X-ray and magnetic tests. The results indicate that the alloy combines good glass forming ability and thermal stability. After heat treatment, the alloy precipitates with a feature of three-dimensional growth, while the α-Fe,Co phase first precipitates, and following the lamellar eutectic precipitate as Fe-B and Co2Si. This ultra-fine α-Fe,Co at low temperatures and the solid solution of non-ferromagnetic elements in the α-Fe,Co at high temperatures decrease the saturation magnetization of the alloy. In addition, the change from antiferromagnetic to ferromagnetic of Mn is confirmed through first-principles density functional theory calculations.

Phase formation, microstructure evolution and strengthening mechanism of Au27.9Ag20.3Cu51.8 noble metal medium-entropy alloy during cold deformation and aging

Au27.9Ag20.3Cu51.8 noble metal medium-entropy alloy (MEA) is commercially applied in the electrical contact field due to the unique advantages, such as excellent chemical stability, outstanding electrical property and good processability. However, the low strength brings the poor deformation resistance and wear resistance in service. Herein, the cold deformation and aging treatment were applied to strengthen Au27.9Ag20.3Cu51.8 noble metal MEA, and the related evolutions of the microstructure, tensile property, and electrical resistivity were experimentally investigated. The phase formation and strengthening mechanisms were theoretically discussed. The results show that Au27.9Ag20.3Cu51.8 MEA is composed of the single-phase face-centered cubic (FCC) solid solution at the initial solution treatment of 750 °C. After the aging at 400 °C for 0.5 h, lamellar discontinuous precipitation (DP), consisting of Cu-rich and Ag-rich phases, forms at the grain boundaries (GBs), and L12-type chemical short-range order (CSRO) precipitates in both the matrix and the Cu-rich phase of DP. After 20% cold deformation, the L12-type CSRO similarly emerges in the matrix. After 20% cold deformation prior to aging at 400 °C for 0.5 h, DP at the GBs and L12-type CSRO in the matrix and the Cu-rich lamellae of DP are observed. The growth kinetics of DP and L12-type CSRO are both slightly promoted by prior cold deformation. Au27.9Ag20.3Cu51.8 MEA wire with single-phase FCC sold solution achieves the yield strength of ∼422 MPa. And, 20% cold deformation prior to aging at 400 °C for 0.5 h raises the yield strength of Au27.9Ag20.3Cu51.8 MEA wire to a peak value of ∼696 MPa. The solid solution strengthening mechanism invariably offers the largest strength contribution during the cold deformation and aging, the strain and precipitation strengthening mechanisms almost equivalently contribute to the strength improvement. The electrical resistivity maintains stable with a small variation during the cold deformation and aging. The findings in this study can provide insights for strengthening the noble metal HEAs or MEAs via traditional strengthening methods, and theoretically support for tailoring the microstructure and properties of the high-performance noble metal HEAs or MEAs.

Kinetic Study of the Aging and Overaging of Alloy Pb0.058%Ca0.12%Sr1.09%Sn for Battery Grids

In this paper, we examine the effect of a small amount of Sn, Sr and Ca on the hardening and the kinetic properties of Pb. Experimentally, we analyze the specific process from the structural hardening evolution to equilibrium of PbCaSrSn alloy occurring in two steps. In the first one, a discontinuous transformation hardening and a continuous precipitation take place. A lamellar discontinuous precipitation that occurs after aging, characterizes the second step. Theoretically, we study the aging and overaging kinetics of the alloy by using the two complimentary methods needed to calculate the apparent activation energies of the Pb0.058%Ca0.12%Sr1.09%Sn associated with the various transformations, characterizing its hardening at 20 and 80 °C. We show that activation energies of aging and overaging of Pb0.058%Ca0.12%Sr1.09%Sn alloy are 25 and 28 kJ/mole, respectively, which are four times lower than the self-diffusion energy of Pb. Moreover, the addition of Ca, Sr and Sn leads to an amplification of the maximum hardness from 5 ± 5% HV to 21 ± 5% HV and an acceleration of the transformation hardening process responsible for aging.

Improvement of microstructure and acquirement of excellent mechanical properties of high-Nb Ti2AlC/TiAl alloy by Ta under ultrasonic action in solid-liquid zone

To promote element diffusion in the solid-liquid two-phase region, optimize solidification microstructure, and improve the matching degree of strength and toughness, Ti–46Al–8Nb-2.6C-xTa (at. %) alloys were prepared by arc melting under the action of ultrasound. The lamellar colony, precipitate phase, elements distribution, and related mechanisms were analyzed. Results show that the relative content of the γ phase decreases, while the relative content of the α2 phase and Ti2AlC phase increases as the addition of Ta increases. The coarse long rod-shaped Ti2AlC transforms into short rod-shaped particles. The lamellar colony size reduces from 32.1 to 18.6 μm, the lamellar spacing reduces from 1.4 to 0.7 μm, and the aspect ratio of Ti2AlC reduces from 5.8 to 2.5 as the addition of Ta increases from 0 to 1.0 at. %. The acoustic streaming effect of ultrasound promotes the diffusion of tantalum in the solid-liquid two-phase region for a certain ultrasonic processing time. Tantalum is a heterogeneous nucleation particle of Ti2AlC particles and causes composition supercooling at the forefront of the solidification interface, which is the main reason for refining the microstructure. Compressive strength increases from 1996 to 2596 MPa and the strain increases from 25.4 to 29.3% as the addition of Ta increases from 0 to 0.6 at. %. The main reasons for improving the properties of alloy are the refinement of the microstructure and the formation of a large number of dislocations.

Corrosion behavior of as-cast AZ91 magnesium alloy with VN particle additions in NaCl solution

The microstructures and corrosion behavior of the as-cast AZ91−xVN (x=0, 0.25, 0.5 and 1 in wt.%) alloys were investigated using optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The results showed that VN can significantly refine and modify the microstructures of AZ91−xVN alloys. The corrosion resistance of the AZ91 alloy was first improved and then deteriorated with the addition of VN particles. The superior corrosion resistance of the as-cast AZ91−0.25VN alloy with the lowest corrosion rate (PW=(1.47±0.06) mm/a) was attributed to the additional grain boundaries. With the further increase of VN content, the amount of the lamellar β-Mg17Al12 precipitation phase increased, and thus the galvanic corrosion between β phase and the α-Mg matrix was promoted, resulting in the deteriorated corrosion resistance of the alloys.

Heterogeneous bimodal microstructure and its formation mechanism of Mg-Gd-Y-Zn-Zr alloy during isothermal compression

Heterogeneous bimodal microstructure and its formation mechanism of Mg-Gd-Y-Zn-Zr alloy during isothermal compression at 450 °C and 0.001 s−1 was investigated in detail. Based on microstructure analysis, Mg-Gd-Y-Zn-Zr alloys with bimodal grain size distribution and bimodal texture distribution were obtained by uniaxial isothermal compression. There were more heavily bimodal levels in grain size and texture at true strain greater than 0.8. There was a significant inhomogeneous plastic deformation between and within the grains in Mg-Gd-Y-Zn-Zr alloy during the deformation, which is attributed to the difference the grain orientation and a large number of intergranular block-shaped LPSO phases. Further studies revealed that particle-stimulated nucleation (PSN) caused by a large intergranular LPSO phases and continuous dynamic recrystallization (CDRX) developed layer by layer toward the grain interior were the main grain refinement mechanisms. This PSN and CDRX mechanism contributed to the fine grains in bimodal grain size distribution and the random texture in bimodal texture distribution. However, the original coarse grains with basal orientation were preserved during deformation due to smaller plastic deformation and energy storage. Meanwhile, grain boundary segregation and intragranular lamellar LPSO precipitate promoted CDRX by retarding DDRX. In addition, the grain boundary pinning effect dominated by grain boundary segregation and intragranular lamellar LPSO precipitate hindered the coarsening of fine DRXed grains, which was the ultimate guarantee for the formation of bimodal microstructure. Ultimately, inhomogeneous plastic deformation, DRX, and grain boundary pinning effect were demonstrated as the necessary conditions for the formation of heterogeneous bimodal microstructure during thermal deformation of Mg-Gd-Y-Zn-Zr alloy.

Significant strain hardening ability of AZ91 magnesium alloy fabricated by spark plasma sintering

The strain hardening behavior of AZ91 alloys fabricated by spark plasma sintering (SPS) under different sintering temperatures was investigated by compression at room temperature. The sintered AZ91 alloys with random texture exhibit high yield strength and significant strain hardening ability. The hardening abilities (including strain hardening rate, strain hardening exponent and hardening capacity) increase with increasing sintering temperature. The strain hardening of sintered AZ91 alloys is dominated by dislocation slip and accompanied with extension twinning. The increment of hardening abilities is mainly due to the increasing of dislocation induced strain hardening because the rate of dislocation propagation is enhanced by coarse-grain. Additionally, the strain hardening induced by twinning is suppressed by fine-grain and intragranular lamellar Mg17Al12 precipitate.

Effect of initial grain structure on the concurrent precipitation and recrystallization of Co37Cr20Ni37Ti3Al3 high-entropy alloy

High performance precipitation strengthened high-entropy alloys (HEAs) can be prepared by concurrent recrystallization and precipitation in the process of aging at intermediate temperatures after rolling. Generally, the homogenized samples are subjected to rolling before aging, where the effects of initial grain structure before rolling on the concurrent recrystallization and precipitation are overlooked. In this study, we revealed the inherited effect of initial grain on the concurrent recrystallization and precipitation in Co37Cr20Ni37Ti3Al3 HEA. The heredity of grain homogeneity to the initial grain structure was revealed, where the initial grain structure influences the homogeneity of strain distribution during rolling and influences the recrystallization in the subsequent aging. Moreover, the inherited effect of the initial grain structure also influences the precipitation behavior. TEM characterization confirmed that the lamellar precipitation decreases, while spherical precipitation increases with the increase of the initial grain size. By tailoring the initial grain size, the strength and ductility of Co37Cr20Ni37Ti3Al3 alloy were simultaneously improved. The present study provides a good understanding of the concurrent recrystallization and precipitation in HEAs.

Unveiling the mechanism of yttrium significantly improving high-temperature oxidation resistance of super-austenitic stainless steel S32654

Aiming at serious catastrophic oxidation problem of super-austenitic stainless steel S32654, the influence of different rare earth elements on its oxidation behavior was comparatively investigated at 1200 °C. The mechanism of Y significantly improving high-temperature oxidation resistance of S32654 was unveiled. The results demonstrated that Y played much better beneficial roles than Ce and La in the initial formation of oxide layer: (1) Y promoted Cr segregation to steel surface to combine with O; (2) its preferential oxidation provided nucleation cores for Cr2O3. Both roles jointly promoted the selective oxidation of Cr and then the formation of protective Cr-rich oxide layer. This provided good prerequisites for inhibiting the formation and volatilization of MoO3. Additionally, Y cation segregation to oxide grain boundaries further promoted the selective oxidation of Cr and Si to form more protective oxide layer. These beneficial roles of Y essentially eliminated the synergistic effects of MoO3 volatilization and lamellar Cr2N precipitation on catastrophic oxidation. Accordingly, the oxidation resistance of Y-bearing S32654 was improved by 22%–45%.

The effects of deformation parameters and cooling rates on the aging behavior of AZ80+0.4%Ce

The extruded AZ80+0.4% Ce magnesium alloy was twisted in the temperature range of 300 - 380 °C by using a Gleeble 3500 thermal simulation test machine with a torsion unit. The deformed cylindrical specimens were cooled at a cooling rate of 10 °C/s or 0.1 °C/s, respectively, and aged at 170 °C. The microstructure analysis results showed that the grain size decreased with increasing specimen radial position from center (SRPC), and that the strong initial basal texture of the extruded magnesium alloy was weakened. Both continuous and discontinuous dynamic recrystallization mechanisms were involved in contributing to the grain refinement for all specimens investigated. And a novel extension twinning induced dynamic recrystallization mechanism was proposed for specimen deformed at 300 °C. For the specimens deformed at 300 °C and 340 °C followed by a slow cooling rate (0.1 °C/s), precipitates of various shapes (β-Mg17Al12), with the dominant precipitates being on the grains boundaries, appeared on the surface section. For specimen deformed at 380 °C, lamellar precipitates (LPS) in the interiors of the grains were predominant. After aging, the LPS still dominated for specimens twisted at 380 °C; however, the LPS gradually decreased with decreasing deformation temperatures from 380 °C to 300 °C. Dynamically precipitated β, especially those decorating the grain boundaries, changed the competition pictures for the LPS and precipitates of other shapes after aging. Interestingly, LPS dominated the areas for the center section of the specimens after aging regardless of deformation temperatures. Low temperature deformation with high SRPC followed by rapid cooling rate increased the micro hardness of the alloy after aging due to refined grain, reduced precipitates size, decreased lamellar spacing as well as strain hardening.

Surface interaction and biomineralization of uranium induced by the living and dead bacterial ghosts of Kocuria sp.

Many researchers investigated that living bacteria could combine with uranium in the water and form bio-minerals. However, the key components and process in promoting the forming of uranium biomineralization are still not very clear. In this study, we investigated the biosorption features and mechanism of living and dead cell wall and cell membrane which including dead bacterial ghosts (D-BGs, Kocuria sp. cells without extracellular polymeric substance-EPS and cytoplasm) and living bacterial ghosts (L-BGs, Kocuria sp. cells without EPS) to interact with U(VI). Macroscopic experiments demonstrated that the maximum capacity of U (VI) by D-BGs up to 82.90%, while the removal ability of L-BGs reduced to 73.03% at pH 6. Added inorganic phosphate could greatly improve the biosorption rate of uranium on cell wall. SEM demonstrated that phosphate could promote amorphous uranium to transform into uranium phosphate (U-P) precipitate in D-BGs. While the lamellar uranium phosphate precipitation was observed on the L-BGs of Kocuria sp. after interacting with uranium. It demonstrated that inactive cell was unable to convert slight precipitations to mineral and L-BGs had ability to form U-P mineralization on the cell surface. Fourier Transform Infrared Spectroscopy (FTIR) results indicated the main functional groups adsorbed U(VI) were PO, C-O, -OH and -COOH. Both X-ray photoelectron spectroscopy (XPS) and FTIR results showed the effect of P element after adsorbing U(VI), indicating phosphate groups is the main biosorption sites for U(VI). Our findings highlight that the necessary inducement of mineralization condition for U(VI) is the metabolic activity of living cells, and adopting analytical pure phosphate to replace secretion of organic, inorganic phosphorus and related enzymes suggested that phosphate is a key regulator of uranium biomineralization.

Effect of Multi-Variant Thermal Treatment on Microstructure Evolution and Mechanical Properties of AlSi10Mg Processed by Direct Metal Laser Sintering and Casting.

This article presents a study on the influence of temperature and time of multi-variant heat treatment on the structure and properties of materials produced in direct metal laser sintering (DMLS) and casting technology. The materials were manufactured in the form of cuboidal elements with a cross-section of 1.5 mm × 15 mm and a length of 60 mm. The samples prepared in this way had a similar volume, but due to the production technology the metal crystallization took place at different rates and directions. In the cast, the direction of heat transfer was toward the mold, and the DMLS was directed locally layer by layer. The small thickness of the cast material allowed reaching conditions similar to the DMLS cooling process. Both DMLS and cast samples show similar mechanical properties (hardness) achieved after long ageing time, i.e., 16 h at 170 °C. The maximum hardness was observed for 8 h. In the DMLS samples, in contrast to cast samples, no lamellar precipitates of silicon were observed, which indicates their better resistance to cracking

Recrystallization Annealing Soaking Time Effect on the Tribological Behavior of Cold Upsetted Low Carbon Steel

This article evaluates the effect of recrystallization annealing soaking time on the tribological behavior of cold upsetted low carbon steel. The 40% cold formed steel was subjected to annealing at 900 °C, for 10, 20, 30, 40, 50 and 60 minutes. The mechanical properties of hardness, tensile strength, yield strength and ductility, measured through specific deformation, as well as the precipitation of carbides through microstructural analysis were examined. In order to analyze the volume of removed material, the wear test was performed using a pin-on-disk tribometer according to ASTM G99. The results showed that the combination of lamellar perlite precipitation and pearlitic interlayer spacing reduction increases the mechanical strength of 1020 steel, reduces ductility, increases friction coefficient and increases wear observed by the volume of removed material increase.