Phase Structure and High-Temperature Mechanical Properties of Two-Phase Fe-25Al-xZr Alloys Compared to Three-Phase Fe-30Al-xZr Alloys

The structure and high-temperature mechanical properties of Fe-30 at. pct Al and Fe-25 at. pct Al alloys with various Zr contents are compared. The scanning electron microscope images in chemical contrast mode (R-BSE) as well as EDS, EBSD, and X-ray diffraction were used to determine the structure and phase composition. The as-cast alloys (both Fe-30Al and Fe-25Al) were observed to be two-phase DO₃/B2 + Laves phase λ ₁ (Fe,Al)₂Zr alloys with typical fine lamellar eutectic areas. During the heat treatment of the Fe-25Al alloys, their structure transformed from a DO₃/B2 matrix with fine lamellar eutectic into λ ₁ globular particles situated in a DO₃/B2 matrix. The same structure of Fe-30Al alloys decomposed into three phases: λ ₁ and τ ₁ Zr(Fe,Al)₁₂ particles in a DO₃/B2 matrix. The hardening in both groups of alloys (Fe-25Al and Fe-30Al) due to the presence of Zr-containing λ ₁ and τ ₁ phases is compared.     

The Development of the Low-Cost Titanium Alloy Containing Cr and Mn Alloying Elements

The α + β-type Ti-4.5Al-6.9Cr-2.3Mn alloy has been theoretically designed on the basis of assessment of the Ti-Al-Cr-Mn thermodynamic system and the relationship between the molybdenum equivalent and mechanical properties of titanium alloys. The alloy is successfully prepared by the split water-cooled copper crucible, and its microstructures and mechanical properties at room temperature are investigated using the OM, SEM, and the universal testing machine. The results show that the Ti-4.5Al-6.9Cr-2.3Mn alloy is an α + β-type alloy which is consistent with the expectation, and its fracture strength, yield strength, and elongation reach 1191.3, 928.4 MPa, and 10.7 pct, respectively. Although there is no strong segregation of alloying elements under the condition of as-cast, the segregation of Cr and Mn is obvious at the grain boundary after thermomechanical treatment.     

Casting of High-Aluminum-Content Mg Alloys Strip by a Horizontal Twin-Roll Caster

This study was aimed to investigate casting of high-aluminum-content Mg alloys strip by a horizontal twin-roll caster. A horizontal-type twin-roll caster was equipped with a nozzle. This nozzle was movable. The roll size was φ300 × W150, and copper rolls were used. The rolling road was very small. It was possible to cast AZ91D and AZ121 magnesium alloys continuously by a horizontal twin-roll caster. There was gloss and no crack. The thickness of as-cast strip of AZ91D was 4.5 mm and that of AZ121 was 4.6 mm, respectively. In the case that roll velocity was 48 m/min, the thickness of as-cast strip of AZ121 was 2.0 mm. A 2.0-mm-thick strip was able to coil, and the diameter was φ500 mm. The microstructures of the as-cast strip of AZ91D and AZ121 magnesium alloys were observed using light optical microscopy. Isometric dendrite crystals were observed at the as-cast strip. The as-cast strip without facing of AZ91D and AZ121 magnesium alloys were able to hot rolling of 75 pct reduction. The surface of the as-rolled sheet was flat and glossy. The tensile strength of the as rolled was 230 MPa and the elongation of as rolled was 4 pct.     

Cryogenic Mechanical Properties of Warm Multi-Pass Caliber-Rolled Fine-Grained Titanium Alloys: Ti-6Al-4V (Normal and ELI Grades) and VT14

The effect of microstructural refinement and the β phase fraction, V _β, on the mechanical properties at cryogenic temperatures (up to 20 K) of two commercially important aerospace titanium alloys: Ti-6Al-4V (normal as well as extra low interstitial grades) and VT14 was examined. Multi-pass caliber rolling in the temperature range of 973 K to 1223 K (700 °C to 950 °C) was employed to refine the microstructure, as V _β was found to increase nonlinearly with the rolling temperature. Detailed microstructural characterization of the alloys after caliber rolling was carried out using optical microscopy (OM), scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD), and transmission electron microscopy (TEM). Complete spheroidization of the primary α laths along with formation of bimodal microstructure occurred when the alloys are rolled at temperatures above 1123 K (850 °C). For rolling temperatures less than 1123 K (850 °C), complete fragmentation of the β phase with limited spheroidization of α laths was observed. The microstructural refinement due to caliber rolling was found to significantly enhance the strength with no penalty on ductility both at room and cryogenic temperatures. This was attributed to a complex interplay between microstructural refinement and reduced transformed β phase fraction. TEM suggests that the serrated stress–strain responses observed in the post-yield deformation regime of specimens tested at 20 K were due to the activation of \( \left\{ {10\bar{1}2} \right\} \) tensile twins.     

Microstructure and High Temperature Impression Creep Properties of Mg–3Ca–xZr (x = 0.3, 0.6, 0.9 wt%) Alloys

The current study has investigated the influence of zirconium (Zr) addition to Mg–3Ca–xZr (x = 0.3, 0.6, 0.9 wt%) alloys prepared using argon arc melting on the microstructure and impression properties at 448–498 K under constant stress of 380 MPa. Microstructural analysis of as-cast Mg–3Ca–xZr alloys showed grain refinement with Zr addition. The observed grain refinement was attributed to the growth restriction effect of Zr in hypoperitectic Mg–3Ca–0.3 wt% Zr alloys. Heterogeneous nucleation of α-Mg in properitectic Zr during solidification resulted in grain refinement of hyperperitectic Mg–3Ca–0.6 wt% Zr and Mg–3Ca–0.9 wt% Zr alloys. The hardness of Mg–3Ca–xZr alloys increased as the amount of Zr increased due to grain refinement and solid solution strengthening of α-Mg by Zr. Creep resistance of Mg–3Ca–xZr alloys increased with the addition of Zr due to solid solution strengthening of α-Mg by Zr. The calculated activation energy (Q_a) for Mg–3Ca samples (131.49 kJ/mol) was the highest among all alloy compositions. The Q_a values for 0.3, 0.6 and 0.9 wt% Zr containing Mg–3Ca alloys were 107.22, 118.18 and 115.24 kJ/mol, respectively.     

Microstructure of high-tensile strength brasses containing silicon and manganese

The morphology, crystallography, chemistry, and distribution of the phases in commercial high-tensile strength brasses containing manganese and silicon with compositions conforming to U.S.A. Specifications C67300 (Cu-35Zn-2.5Mn-lSi) and C67400 (Cu-35Zn-2.5Mn-lSi-l.5Al) have been studied. The wrought and cast microstructures of both types of alloys consist of the copper-rich feea phase, ordered B2β’ phase, and a manganese silicide Mn₅Si₃, with the crystal structure D8₈. Particles of Mn₅Si₃ are distributed uniformly in the as-cast alloy C67300 but tend to concentrate at theβ′ boundaries in alloy C67400. Studies of the development of the microstructure show that Mn₅Si₃ particles form from the liquid and are also precipitated from solid solution. During cooling, the α phase precipitates at a higher temperature in alloy C67300 (800 °C) than in alloy C67400 (500 °C); nucleation of the α phase occurs on Mn₅Si₃ particles in alloy C67400. Tiny Mn₅Si₃ precipitates are formed in both alloys upon quenching from temperatures near the solidus. When the quenched specimens are tempered at temperatures between 400 °C and 500 CC, all of theβ′ phase transforms to α in alloy C67300, while in alloy C67400, α precipitation occurs at theβ′ boundaries and shows a Widmanstätten morphology.     

Synthesis and Characterization of Novel Chromium-Free Nickel Alloy Electrode Materials

The synthesis of two Cr-free nickel-based alloys designated as 1S with 6.5 pct Mn and 2H without Mn of compositions varying between 40 to 43.5Ni, 20Mo, 22 to 25Fe, 10Cu, 6.5 to 0Mn, 1Ti, and 0.5Al (wt pct) as filler materials for TIG welding application was performed. New filler materials were developed to reduce carcinogenic hexavalent chromium (Cr⁶⁺) fumes generated during the welding of 300 series austenitic stainless steel. The Cr-free nickel alloys were characterized for microstructure and mechanical properties. The developed alloys showed good microstructure stability in as-cast and solution-treated conditions. A material properties simulation software JMatPro predicted that 2H alloy has 2 wt pct more γ (solid solution) phase than in 1S but has 2.2 wt pct less γ′ (strengthening precipitates) phase than in 1S alloy. The tensile strength of 1S alloy was about 2.2 pct more than 2H. The solution treatment of both alloys decreased the hardness, tensile and yield strengths by about 21 pct but ductility improved by about 17 pct. Fracture studies of both alloys showed the ductile mode of failure.     

Elevated-Temperature Mechanical Behavior of As-Cast and Wrought Ti-6Al-4V-1B

This work studied the effect of processing on the elevated-temperature [728 K (455 °C)] fatigue deformation behavior of Ti-6Al-4V-1B for maximum applied stresses between 300 to 700 MPa (R = 0.1, 5 Hz). The alloy was evaluated in the as-cast form as well as in three wrought forms: cast-and-extruded, powder metallurgy (PM) rolled, and PM extruded. Processing caused significant differences in the microstructure, which in turn impacted the fatigue properties. The PM-extruded material exhibited a fine equiaxed α + β microstructure and the greatest fatigue resistance among all the studied materials. The β-phase field extrusion followed by cooling resulted in a strong α-phase texture in which the basal plane was predominately oriented perpendicular to the extrusion axis. The TiB whiskers were also aligned in the extrusion direction. The α-phase texture in the extrusions resulted in tensile-strength anisotropy. The tensile strength in the transverse orientation was lower than that in the longitudinal orientation, but the strength in the transverse orientation remained greater than that for the as-cast Ti-6Al-4V. The ratcheting behavior during fatigue is also discussed.     

Effect of Mn Substitution on Microstructure Evolution and Magnetic Phase Transition in La(Fe1−x Mn x )10.8Co0.7Si1.5 Compounds

The influences of Mn substitution for Fe on microstructures of La(Fe_1?x Mn _x )_10.8Co_0.7Si_1.5 (x = 0, 0.01, 0.02, 0.03) alloys in both the as-cast state and the annealed state have been studied. The results show that Mn substitution promotes the fining of the as-cast microstructure and increases the formation of 1:13 phase significantly when annealed. An almost single 1:13 phase is obtained for x = 0.01 when annealed at 1373 K (1100 °C) for 3 days, while a large amount of impurity phases is still present for x = 0. By increasing the amount of Mn to x = 0.02, a more purified annealed microstructure can be obtained. However, further substitution of Mn up to x = 0.03 is harmful for the formation of 1:13 phase. The Curie temperature T _C of the annealed La(Fe_1?x Mn _x )_10.8Co_0.7Si_1.5 (x = 0, 0.01, 0.02, 0.03) varies monotonously with Mn content x, decreasing from ~279 K (6 °C) for x = 0 to ~236 K (?37 °C) for x = 0.03. When x = 0.01, a higher maximum entropy change (?ΔS)_max of 5.3 J/(kgK) and relative cooling power (RCP) of 166 J/kg can be obtained under a magnetic field of 2T. Further substitution of Mn (x = 0.02) results in a slight decrease of (?ΔS)_max, whereas a larger RCP can still be kept.     

Influence of Extrusion on the Microstructure and Mechanical Behavior of Mg-9Li-3Al-xSr Alloys

Mg-9Li-3Al-xSr (LA93-xSr, x = 0, 1.5, 2.5, and 3.5 wt pct) alloys were cast and extruded at 533 K (260 °C) with an extrusion ratio of 28. The microstructure and mechanical response are reported and discussed paying particular attention to the influence of extrusion and Sr content on phase composition, strength, and ductility. The results of the current study show that LA93-xSr alloys contain both α-Mg (hcp) and β-Li (bcc) matrix phases. Moreover, the addition of Sr refines the grain size in the as-cast alloys and leads to the formation of the intermetallic compound (Al₄Sr). Our results show significant grain refinement during extrusion and almost no influence of Sr content on the grain size of the extruded alloys. The microstructure evolution during extrusion is governed by continuous dynamic recrystallization (CDRX) in the α-Mg phase, whereas discontinuous dynamic recrystallization (DDRX) occurs in the β-Li phase. The mechanical behavior of the extruded LA93-xSr alloy is discussed in terms of grain refinement and dislocation strengthening. The tensile strength of the extruded alloys first increases and then decreases, whereas the elongation decreases monotonically with increasing Sr; in contrast, hardness increases for all Sr compositions studied herein. Specifically, when Sr content is 2.5 wt pct, the extruded Mg-9Li-3Al-2.5Sr (LAJ932) alloy exhibits a favorable combination of strength and ductility with an ultimate tensile strength of 235 MPa, yield strength of 221 MPa, and an elongation of 19.4 pct.     

Melting and Microstructure Analysis of β-Ti Alloy Ti–5Al–5Mo–5V–1Cr–1Fe With and Without Boron

β-Titanium alloys form one of the most versatile classes of structural materials due to their high specific strength, good hardenability, crack propagation resistance and substantial ductility. β-Titanium alloy with a composition (in wt%) of Ti–5Al–5Mo–5V–1Cr–1Fe was processed by double vacuum arc remelting route. In the present work, the effect of boron addition (up to 0.12 wt%) on the as-cast microstructure and β-transus (T_β) of the alloy was studied using characterization tools like optical microscopy, electron back scattered diffraction, scanning electron microscopy, differential scanning calorimetry (DSC) and dilatometry. It was observed that boron addition has resulted in refinement of the as-cast microstructure due to precipitation of titanium boride whiskers along the grain boundaries. The DSC and dilatometry studies on the as-cast alloy revealed significant effect of boron addition on thermal stability of the alloy.     

Characterization of Continuous and Discontinuous Precipitation Phases in Pd-Rich Precious Metal Alloys

Aberration-corrected scanning transmission electron microscopy (AC-STEM), X-ray diffraction (XRD), electron backscatter diffraction, and electron probe microanalysis were applied to characterize continuous and discontinuous phase formation in precious metal alloys used in electrical contacts. The Pd-rich Paliney^® (^®Paliney is tradename of Deringer-Ney Inc., Bloomfield, CT) alloys contain Pd, Ag, Cu, Au, Pt (and Zn or Ni). With aging at 755 K (482 °C), nanometer-scale chemistry modulation was observed indicating spinodal decomposition. An ordered body-centered tetragonal (bct) structure was also observed with AC-STEM after the 755 K (482 °C) aging treatment and another phase, tentatively identified as β-Cu₃Pd₄Zn, was found by microscopy and XRD after prolonged holds at higher temperatures. During slow cooling or isothermal holds at high temperature [755 K to 973 K (482 °C to 700 °C)], a two-phase lamellar structure develops along grain boundaries by discontinuous precipitation. XRD and AC-STEM showed that the lamellar structure was comprised of Ag-rich and Cu-rich fcc phases (α ₁ and α ₂). The phases are discussed in relation to a pseudo-ternary diagram based on Ag-Cu-Pd, which provides a simplified representation of the discontinuous phase compositions in the multi-component alloy system.     

Electron Microscopic Study on the Suction Cast In Situ Ti-Fe-Sn Ultrafine Composites

The current investigation reports detailed study on the microstructural evolution in the suction cast hypereutectic Ti₇₁Fe_29?x Sn _x alloys during Sn addition with x = 0, 2, 2.5, 3, 3.85, 4.5, 6, and 10 at. pct and the solidification of these ternary alloys using SEM and TEM. These alloys have been prepared by melting high-purity elements using vacuum arc melting furnace under high-purity argon atmosphere. This was followed by suction casting these alloys in the water-cooled split Cu molds of diameters, ? = 1 and 3 mm, under argon atmosphere. The results indicate the formation of binary eutectic between bcc solid solution ??-Ti and B2 FeTi in all alloys. ??-Ti undergoes eutectoid transformation, ??-Ti ?? ??-Ti + FeTi, during subsequent solid-state cooling, leading to formation of hcp ??-Ti and FeTi. For alloys x < 2, the primary FeTi forms from the liquid before the formation of eutectic with minute scale Ti₃Sn phase. For alloys with 2 ?? x ?? 10, the liquid is found to undergo ternary quasi-peritectic reaction with primary Ti₃Sn, L+Ti₃Sn ?? ??-Ti+FeTi, leading to formation of another kind of FeTi. In all the other alloy compositions (3.85 ?? x ?? 10), Ti₃Sn and FeTi dendrites are observed in the suction cast alloys with profuse amount of Ti₃Sn being formed for alloys with x ?? 4.5. The current study conclusively proves that the liquid undergoes ternary quasi-peritectic reaction involving four phases, L + Ti₃Sn ?? ??-Ti + FeTi, which lies at the invariant point Ti_69.2±0.8Fe_27.4±0.7Sn_3.4±0.2 (denoted by P). Below P, there is one univariant reaction, i.e., L ?? ??-Ti + FeTi for all alloy compositions, whereas above P, liquid undergoes one of the univariant reactions, i.e., L + ??-Ti ?? Ti₃Sn (Sn = 2, 2.5, 3, and 4.5 at. pct) or L + FeTi ?? Ti₃Sn for alloys (Sn = 6, 10 at. pct). For alloy with Sn = 3.85 at. pct, the ternary quasi-peritectic reaction is co-operated by two monovariant eutectic reactions, i.e., L ?? ??-Ti + FeTi below P and L ?? FeTi + Ti₃Sn above P. Detailed microstructural information allows us to construct liquidus projection of the investigated alloys. The results are critically discussed in the light of available literature data.     

Effect of Partial Substitution of Mn for Ni on Mechanical Properties of Friction Stir Processed Hypoeutectic Al-Ni Alloys

In this study, the mechanical properties of as-cast and FSPed Al-2Ni-xMn alloys (x?=?1, 2, and 4 wt pct) were investigated and compared with those of the as-cast and FSPed Al-4Ni alloy. According to the results, the substitution of 2 wt pct Mn for 2 wt pct Ni leads to the formation of fine Mn-rich intermetallics in the microstructure increasing the tensile strength, microhardness, fracture toughness, and specific strength of alloy by 22, 56, 45, and 35 pct, respectively. At higher Mn concentrations, the formation of large Mn-rich platelets in the microstructure reduces the tensile properties. Friction stir processing at 12 mm/min and 1600 rpm significantly enhances both the strength and ductility of the alloy. The tensile strength, yield strength, fracture strain, fracture toughness, microhardness, and specific strength of FSPed Al-2Ni-4Mn alloy improved by 97, 83, 30, 380, 152, and 110  pct, respectively, as compared to those of the as-cast Al-4Ni alloy. This can be attributed to dispersion strengthening of Ni- and Mn-rich dispersoids, formation of ultrafine grains, and elimination of casting defects. The fractography results also show that the brittle fracture mode of the as-cast Mn-rich alloys turns to a more ductile mode, comprising fine and equiaxed dimples in FSPed samples.     

Effect of Temperature and Composition on NiAl Precipitation and Morphology in Fe-Ni-Al Alloys

NiAl-strengthened ferritic alloys have been of particular interest because of their possibilities as a high-temperature material for power-generation purposes. In the present work, the effect of temperature and composition on the precipitation of the NiAl (β′) phase was studied using a diffusion couple made of alloys Fe_0.50Ni_0.25Al_0.25 and Fe_0.80Ni_0.08Al_0.12. The composition gradient was obtained with a diffusion annealing treatment at 1373 K (1100°C), and the precipitation was promoted by aging at 1123 K, 1173 K and 1223 K (850 °C, 900 °C and 950 °C) for 5 hours. The formation of a supersaturated solid solution and the precipitation of the β′ phase were obtained after the diffusion annealing and aging treatments, respectively. A gradual increase in the size and volumetric fraction of the precipitates was evident in compositions with higher NiAl. This promoted changes in the precipitate morphology that followed the sequence: rounded cuboids → plates → irregular (maze-like). Compositions with a low β′ volumetric fraction followed the predicted size distributions of the Lifshitz-Slyozov-Wagner (LSW) theory. Finally, it was observed that the hardness tends to increase inversely to the Fe content and decreases only because of precipitate coarsening. The achieved results provide new information regarding the dependency of the morphology of β′ precipitates with composition and temperature.     

Physical and Structural Characterization of a Monocrystalline Cu-13.7Al-4.2Ni Alloy Subjected to Thermal Cycling Treatments

A monocrystalline alloy with nominal 82wt pctCu-13.7wt pctAl-4.2wt pctNi composition and exhibiting reversible martensitic transformation (RMT) was subjected to multiple heating and cooling cycles within the RMT range of critical temperatures. Both untreated and cyclic treated alloy samples were characterized by X-ray diffraction, optical microscopy, differential scanning calorimetry, and Vickers microhardness. The results indicated that the alloy presents a complex RMT behavior disclosing a sequence of transformation steps: β ₁ ? R and R ? β′₁ + γ′₁ as well as possible β ₁ ? β′₁ and β′₁ ? γ′₁ direct reactions. The thermal cycling treatment inhibits the development of γ′₁ martensite without much change in both the physical and microstructure characteristics. This suggests a good resistance of the alloy to irreversible structural changes.     

Phase Transformation Textures in Hot-Rolled Binary Ti-Nb Alloys

The present work describes the phase transformation textures of three alloys, namely Ti-8Nb, Ti-12Nb, and Ti-16Nb after β and α + β solution treatments with different cooling rates. The strong, moderate, and weak variant selections have been observed depending on the alloy compositions and cooling rates. The β solution treated and water quenched (STWQ) specimens always exhibit a higher overall intensity than those of β solution treated and furnace cooled (STFC) specimens. This has been attributed to the presence of β phase, which has inhibited the growth of selected variants during cooling. The evidence of texture memory has also been observed after α → β→ α and α″ → β → α″ transformations. A combined effect of α _p, β, and ω phases has introduced different textures after α+β heat treatment than those of β heat-treated specimens. Extent of anisotropy in pole figures is more in water quenched (WQ) than those of furnace cooling (FC) specimens due to the development of equivalent orientations of individual crystallites during slow cooling.     

Phase Transformation Studies in U–xZr (x = 2, 5, 10 wt%) Alloys Using Dynamic Calorimetry

The thermo-kinetics aspects of phase transformations in U rich U–xZr binary alloys, with x = 2, 5 and 10 wt% Zr have been investigated using dynamic calorimetry. The on-heating and cooling transformations at controlled scan rates in the range, 1–99 K min^?1, have been monitored and the following transformation sequence is obtained at slow heating (3 K min^?1) of a U–2Zr alloy: (i) α or α′ (distorted orthorhombic martensite) + δ(UZr₂) → α + γ₂ (bcc phase enriched in Zr); (ii) α + γ₂ → β (tetragonal) + γ₂; (iii) β + γ₂ → β + γ₁ (bcc phase enriched in U); (iv) β + γ₁ → γ; (v) γ (bcc) → liquid (melting). Similar transformation sequence for other compositions with varying enthalpy effects has been witnessed for 5 and 10 Zr alloys. The observed transformation characteristics are rationalized for the effect of Zr content and heating/cooling rate variations.     

Improving the Elevated-Temperature Properties by Two-Step Heat Treatments in Al-Mn-Mg 3004 Alloys

In the present work, two-step heat treatments with preheating at different temperatures (175 °C, 250 °C, and 330 °C) as the first step followed by the peak precipitation treatment (375 °C/48 h) as the second step were performed in Al-Mn-Mg 3004 alloys to study their effects on the formation of dispersoids and the evolution of the elevated-temperature strength and creep resistance. During the two-step heat treatments, the microhardness is gradually increased with increasing time to a plateau after 24 hours when first treated at 250 °C and 330 °C, while there is a minor decrease with time when first treated at 175 °C. Results show that both the yield strength (YS) and creep resistance at 300 °C reach the peak values after the two-step treatment of 250 °C/24 h + 375 °C/48 h. The formation of dispersoids is greatly related to the type and size of pre-existing Mg₂Si precipitated during the preheating treatments. It was found that coarse rodlike β^′-Mg₂Si strongly promotes the nucleation of dispersoids, while fine needle like β^″-Mg₂Si has less influence. Under optimized two-step heat treatment and modified alloying elements, the YS at 300 °C can reach as high as 97 MPa with the minimum creep rate of 2.2 × 10^?9 s^?1 at 300 °C in Al-Mn-Mg 3004 alloys, enabling them as one of the most promising candidates in lightweight aluminum alloys for elevated-temperature applications.     

Effect of Pb Addition on the Discontinuous and Continuous Mg17Al12-β Precipitate During Solidification of AZ91 Magnesium Alloy

The purpose of this study is to investigate the effect of varying Pb additions on the precipitation sequence of the as-cast and aged AZ91 alloy. The amount of discontinuous precipitate gets reduced by increasing the Pb addition. The phase fraction of as-cast and aged alloys demonstrates that by Pb addition Mg₁₇Al₁₂ phase is reduced to 37.7 and 38.7 % respectively.