DIFFUSION PHENOMENA AND MICROSTRUCTURE STABILITY OF Ni－Cr－Al－Y－Si COATING ON THENi_3Al BASED ALLOY SUBSTRATE

ＤＩＦＦＵＳＩＯＮＰＨＥＮＯＭＥＮＡＡＮＤＭＩＣＲＯＳＴＲＵＣＴＵＲＥＳＴＡＢＩＬＩＴＹＯＦＮｉ－Ｃｒ－Ａｌ－Ｙ－ＳｉＣＯＡＴＩＮＧＯＮＴＨＥＮｉ_３ＡｌＢＡＳＥＤＡＬＬＯＹＳＵＢＳＴＲＡＴＥＺ．Ｐ．Ｘｉｎｇ;Ｙ．Ｆ．Ｈａｎ;Ｙ．Ｌ．ＪｉａｎｄＭ．Ｇ?..     

DSC STUDY OF MARTENSITIC TRANSFORMATION KINETICS IN A Cu－Zn－Al－Mn－Ni SHAPE MEMORY ALLOY

ＤＳＣＳＴＵＤＹＯＦＭＡＲＴＥＮＳＩＴＩＣＴＲＡＮＳＦＯＲＭＡＴＩＯＮＫＩＮＥＴＩＣＳＩＮＡＣｕ－Ｚｎ－Ａｌ－Ｍｎ－ＮｉＳＨＡＰＥＭＥＭＯＲＹＡＬＬＯＹＧＥＮＧＧｕｉｌｉ;ＢＡＩＹｕｊｕｎ;ＰＥＮＧＱｉｆｅｎｇ（ＩｎｓｔｉｔｕｔｅｆｏｒＭａｔｅｒｉａ...     

EFFECT OF HIGH TEMPERATURE DEFORMATlON ON MORPHOLOGY OF Nd－RICH PHASE PARTICLES IN Ti－5Al－4Sn－2Zr－1MO－0．25Si－1Nd ALLOY

ＥＦＦＥＣＴＯＦＨＩＧＨＴＥＭＰＥＲＡＴＵＲＥＤＥＦＯＲＭＡＴｌＯＮＯＮＭＯＲＰＨＯＬＯＧＹＯＦＮｄ－ＲＩＣＨＰＨＡＳＥＰＡＲＴＩＣＬＥＳＩＮＴｉ－５Ａｌ－４Ｓｎ－２Ｚｒ－１ＭＯ－０．２５Ｓｉ－１ＮｄＡＬＬＯＹ￥ＬＩＧｅｐｉｎｇ;ＧＵＡＮＳｈａｏｘｕ...     

MICROSTRUCTURE AND TENSILE PROPERTIES OF RAPIDLY SOLIDIFIED Al－3．8Li－0．8Mg－0．4Cu－0．13Zr ALLOY PREPARED BY SPRAY DEPOSITION

ＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＴＥＮＳＩＬＥＰＲＯＰＥＲＴＩＥＳＯＦＲＡＰＩＤＬＹＳＯＬＩＤＩＦＩＥＤＡｌ－３．８Ｌｉ－０．８Ｍｇ－０．４Ｃｕ－０．１３ＺｒＡＬＬＯＹＰＲＥＰＡＲＥＤＢＹＳＰＲＡＹＤＥＰＯＳＩＴＩＯＮＣＵＩＣｈｅｎｇｓｏｎｇ;ＦＡ...     

INVESTIGATION ON THIN－WALL EFFECT OF A DIRECTIONALLY SOLIDIFIED SUPERALLOY BY USING TUBULAR SPECIMENS

ＩＮＶＥＳＴＩＧＡＴＩＯＮＯＮＴＨＩＮ－ＷＡＬＬＥＦＦＥＣＴＯＦＡＤＩＲＥＣＴＩＯＮＡＬＬＹＳＯＬＩＤＩＦＩＥＤＳＵＰＥＲＡＬＬＯＹＢＹＵＳＩＮＧＴＵＢＵＬＡＲＳＰＥＣＩＭＥＮＳＲ．Ｚ．ＣｈｅｎａｎｄＨ．Ｗ．Ｚｈａｎｇ（ＢｅｉｊｉｎｇＩｎｓｔｉｔｕｔ...     

EFFECT OF TRACE ELEMENTS P AND Mn ON THE MICROSTRUCTURE AND HYDROGEN EMBRITTLEMENT OF AN Fe－Ni－Co BASED SUPERALLOY

ＥＦＦＥＣＴＯＦＴＲＡＣＥＥＬＥＭＥＮＴＳＰＡＮＤＭｎＯＮＴＨＥＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＨＹＤＲＯＧＥＮＥＭＢＲＩＴＴＬＥＭＥＮＴＯＦＡＮＦｅ－Ｎｉ－ＣｏＢＡＳＥＤＳＵＰＥＲＡＬＬＯＹＷＡＮＧＡｎｃｈｕａｎ;ＹＡＮＧＫｅ;ＦＡＮＣｕｎｇａｎ...     

THE EFFECT OF SILICON ADDITIVE ON THESTRUCTURE AND PROPERTIES OFC－B_4C－SiC COMPOSITE

ＴＨＥＥＦＦＥＣＴＯＦＳＩＬＩＣＯＮＡＤＤＩＴＩＶＥＯＮＴＨＥＳＴＲＵＣＴＵＲＥ　ＡＮＤＰＲＯＰＥＲＴＩＥＳＯＦＣ－Ｂ_４Ｃ－ＳｉＣＣＯＭＰＯＳＩＴＥＨＵＡＮＧＱｉｚｈｏｎｇ;ＹＡＮＧＱｚａｏｑｉｎａｎｄＷＵＬｉｊｕｎ（ＰｏｗｄｅｒＭｅｔａｌｌｕｒｇ?..     

EFFECT OF P，S AND Si ON THE SOLIDIFICATION，SEGREGATION，MICROSTRUCTURE AND MECHANICAL PROPERTIES IN Fe－Ni BASE SUPERALLOYS

ＥＦＦＥＣＴＯＦＰ,ＳＡＮＤＳｉＯＮＴＨＥＳＯＬＩＤＩＦＩＣＡＴＩＯＮ,ＳＥＧＲＥＧＡＴＩＯＮ,ＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＩＮＦｅ－ＮｉＢＡＳＥＳＵＰＥＲＡＬＬＯＹＳＺ．Ｑ．Ｈｕ;Ｗ．Ｒ．ＳｕｎａｎｄＳ...     

INFLUENCES OF SULPHUREOUS IMPURITY AND MICROSHRINKAGE ON HAC BEHAVIOR OF SUPER－STRENGTH STEEL

ＩＮＦＬＵＥＮＣＥＳＯＦＳＵＬＰＨＵＲＥＯＵＳＩＭＰＵＲＩＴＹＡＮＤＭＩＣＲＯＳＨＲＩＮＫＡＧＥＯＮＨＡＣＢＥＨＡＶＩＯＲＯＦＳＵＰＥＲ－ＳＴＲＥＮＧＴＨＳＴＥＥＬＳ．Ｋ．Ｈｅ;Ｇ．Ｓ．ＷａｎｇａｎｄＳ．Ｎ．Ｗａｎｇ（Ｂｅｉｊｉｎｇｉｎｓｔｉｔｕｔｅ...     

STRAIN INDUCED STRUCTURAL TRANSITION OF INTERFACES AND TWINS IN A HOT－DEFORMED DUAL－PHASE TIAL ALLOY

ＳＴＲＡＩＮＩＮＤＵＣＥＤＳＴＲＵＣＴＵＲＡＬＴＲＡＮＳＩＴＩＯＮＯＦＩＮＴＥＲＦＡＣＥＳＡＮＤＴＷＩＮＳＩＮＡＨＯＴ－ＤＥＦＯＲＭＥＤＤＵＡＬ－ＰＨＡＳＥＴＩＡＬＡＬＬＯＹＣＨＥＮＧｕｏＦｉａｎｇ；ＷＡＮＧＪｉｎｇｕｏ；ＺＨＡＮＧＬｉｃｈｕｎａｎｄ...     

Structure and properties of cast and splat-quenched high-entropy Al–Cu–Fe–Ni–Si alloys

The effect of the composition and cooling rate of the melt on the microhardness, phase composition, and fine-structure parameters of as-cast and splat-quenched (SQ) high-entropy (HE) Al–Cu–Fe–Ni–Si alloys was studied. The quenching was performed by conventional splat-cooling technique. The cooling rate was estimated to be ~10⁶ K/s. Components of the studied HE alloys were selected taking into account both criteria for designing and estimating their phase composition, which are available in the literature and based on the calculations of the entropy and enthalpy of mixing, and the difference between atomic radii of components as well. According to X-ray diffraction data, the majority of studied Al–Cu–Fe–Ni–Si compositions are two-phase HE alloys, the structure of which consists of disordered solid solutions with bcc and fcc structures. At the same time, the Al_0.5CuFeNi alloy is single-phase in terms of X-ray diffraction and has an fcc structure. The studied alloys in the as-cast state have a dendritic structure, whereas, after splat quenching, the uniform small-grained structure is formed. It was found that, as the volume fraction of bcc solid solution in the studied HE alloys increases, the microhardness increases; the as-cast HE Al–Cu–Fe–Ni–Si alloys are characterized by higher microhardness compared to that of splat-quenched alloys. This is likely due to the more equilibrium multiphase state of as-cast alloys.     

Effects of Mo substituted Nb on magnetic properties of Finemet alloy

Different Mo contents have been added into traditional Finemet alloy to form Fe73.5Cu1Nb3-x MoxSil3B9.5( x = 0 - 3) alloys. The change in DC and AC magnetic properties with Mo for Nb substimtlon was investigated. The results show that, with adding Mo, although the DC relative permeability decreases and the coercive force increases slightly,the saturation flux density Bs can be increased, and the core loss of the alloy can be decreased. The AC permeability of samples contained Mo is higher than that of alloy without Mo content. Fe73.sCu1Nb1Mo2Si13B9.5 alloy has the highest saturation flux density Bs. Fe73.sCu1Nb2Mo1Si13B9.5 alloy has the best frequency dependence on the AC permeability and core loss.     

Correlation between microstructure and properties of fine grained Mo–Mo3Si–Mo5SiB2 alloys

Three phase α-Mo–Mo₃Si–Mo₅SiB₂ alloys of various compositions, namely Mo–6Si–5B, Mo–9Si–8B, Mo–10Si–10B and Mo–13Si–12B (at.%) were processed by a powder metallurgical (PM) route. Increasing the Si and B concentration in these Mo–Si–B alloys resulted in increasing volume fractions of the intermetallic phases Mo₃Si (A15) and Mo₅SiB₂ (T2) and the distribution of the three phases present in these alloys was dependent on the volume fractions of the individual phases. Above volume fractions of about fifty percent, bcc Mo solid solution (α-Mo) formed the matrix. Consequently, Mo–6Si–5B and Mo–9Si–8B alloys, which possessed a continuous α-Mo matrix provided increased fracture toughness at ambient temperatures. Additionally, a decreased BDTT of about 950 °C is caused by the homogeneous α-Mo matrix. In contrast, Mo–13Si–12B with 65 vol.% of the intermetallic phases that formed the matrix phase in this material had a BDTT value higher than 1100 °C, while the strength at elevated temperatures up to 1300 °C was significantly increased compared to alloys that have the α-Mo matrix. Alloy compositions with ≥50 vol.% of intermetallic phases (corresponding to alloys containing a minimum of 9 at.% Si and 8 at.% B) were oxidation resistant with minimal mass loss under cyclic conditions for 150 h at 1100 °C due to the formation of a dense borosilicate glass layer that protects the material surface.     

NEWLY-DEVELOPED AND CHEAP NANOCRYSTALLINE Fe-Cu-Nb-Mo-Si-B ALLOYS FOR SWITCHING MODE POWER SUPPLY

1.IntroductionFe--basednanocrystallinealloysexhibitmuchsuperiorsyntheticalsoftmagneticpropertiestothoseofpowerMn--Znferrites,whichisveryfavorableformakingmagneticcoreofmaintransformerinswitchingmodepowersupplywithlargeroutputpower.Thepreviously-developedandtypicalnanocrystallineFe,,.,Cu,Nb,Si,,.,B,11]andFe73.ICul.2Nb,.,Si,,.,B,,lz]containmoreexpensiveNbandtheiras--quenchedamorphousribbonsareratherbrittle.PartlyreplacingNbbymuchcheaperMo,wehavedevelopedtwonewtypenanocrystallineFe73.SCu1…     

Microstructural evolution of direct chill cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy during solution treatment

Heat treatment has important influence on the microstructure and mechanical properties of Al-Si alloys. The most common used heat treatment method for these alloys is solution treatment followed by age-hardening. This paper investigates the microstructural evolution of a direct chill (DC) cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy after solution treated at 500, 510, 520 and 530℃, respectively for different times. The major phases observed in the as-cast alloy are α-aluminum dendrite, primary Si particle, eutectic Si, Al7Cu4Ni, Al5Cu2Mg8Si6, Al15(Cr, Fe, Ni, Cu)4Si2 and Al2Cu. The Al2Cu phase dissolves completely after being solution treated for 2 h at 500℃, while the eutectic Si, Al5Cu2Mg8Si6 and Al15(Cr, Fe, Ni, Cu)4Si2 phases are insoluble. In addition, the Al7Cu4Ni phase is substituted by the Al3CuNi phase. The α-aluminum dendrite network disappears when the solution temperature is increased to 530℃. Incipient melting of the Al2Cu-rich eutectic mixture occurrs at 520℃, and melting of the Al5Cu2Mg8Si6 and Al3CuNi phases is observed at a solution temperature of 530℃. The void formation of the structure and deterioration of the mechanical properties are found in samples solution treated at 530℃.     

Effects of Solution Treatment on the Microstructure and Mechanical Properties of Al-16.9Si-4.5Cu-0.15Mg Alloy

In this paper, the microstructure and mechanical properties of Al-Si-Cu-Mg casting alloy under different solution conditions were investigated by optical metallographic and mechanical property test. The results show that the cast alloys were composed of α-Al, primary Si, eutectic Si, Al2Cu and Al7Cu2Fe phases. Three changes took place during solution treatment: Firstly, with the increase of solution temperature and the solution holding time extension, more and more Al2Cu phase was dissolved into the matrix; Secondly, with the increase of solution temperature and the solution holding time extension, morphology of eutectic Si, Al7Cu2Fe and other insoluble phases changed into more round; Thirdly, at the fixed solution temperature, if the solution time extended too long, it would cause grains, eutectic Si and other insoluble phases aggregated and coarsened. About mechanical properties, when the solution time was fixed, the hardness, tensile strength and the yield strength of the Al-Si-Cu-Mg alloy treated by T6 enhanced while the solution temperature increasing, and when the solution temperature was fixed, the ultimate tensile strength and the elongation of the Al-Si-Cu-Mg alloy treated by T6 increased at first and then decreased while the solution time increasing, but the hardness of the alloys affected less by the solution time.     

Oxidation behaviour of Mo–Si–B–(Al,Ce) ultrafine-eutectic dendrite composites in the temperature range of 500–700 °C

A comparative study has been carried out to investigate the effects of Al and/or Ce additions on microstructure of Mo–Si–B alloys and their isothermal oxidation behaviour at 500 and 700 °C in laboratory air for 24 h. Microstructure of arc melted Mo–Si–B–(Al, Ce) alloys consists of bcc α-Mo dendrites embedded in ultrafine lamellar Mo₃Si and Mo₅SiB₂ eutectic matrix. Isothermal oxidation kinetics of ultrafine structured Mo–Si–B alloy at 500 °C has been found to show hardly any mass change during 24 h exposure. Addition of Al to Mo–Si–B alloy refines the microstructure, decreases the net mass loss at 700 °C by ～43%, whereas Ce does not bring about any significant change. The enhanced oxidation resistance of Mo–Si–B–Al alloy is due to the formation of Al–O rich inter-layer at the alloy/oxide interface along with the formation of a protective and dense Al₂(MoO₄)₃ outer layer, which reduces the sublimation of MoO₃ at 700 °C. Various transient/complex oxides formed on the alloys during their high temperature exposure have been examined to determine the oxidation mechanisms.     

不同状态FeCr8P13B5和FeCr8P13C7合金的耐蚀性能

本文以电化学方法(动电位极化曲线测量)和全浸法考察了不同状态(无定形态、无定形合金退火态以及晶态)FeCr8P13B5和FeCr8P13C7合金在氯离子介质中的耐蚀性能,结果表明(1)无定形FeCr8 P13 B5和FeCr8P13C7合金都具有优异的耐蚀性能。它们的动电位极化曲线十分相似,当极代电压为+1.5伏(SCE)以下时。试样不出现破裂电位Eb,钝态电流维持在10微安/厘米~2以下;这两种无定形耐蚀合金在30℃的0.5N-2.5NHCl、40和60℃的10％,FeCl_3、6H_2O、60℃的3.5％NaCl以及30℃的1MH_2SO_4+0.5MNaCl中全浸168小时其腐蚀速率为10~(-3)-10~(-4)毫米/年。(2)无定形FeCr8P1385和FeCr8P13C7合金经500℃1小时真空退火(晶化)处理后,后者的耐蚀性能急剧恶化,而前者仍保持无定形状态的优异耐腐蚀性能。电化学测量与全浸试验所得的结果是一致的。     

Effect of heat treatment on tensile and fatigue deformation behavior of extruded Al-12 wt%Si alloy

This study investigated the effect of heat treatment on tensile and high-cycle fatigue deformation behavior of extruded Al-12 wt%Si alloy. The material used in this study was extruded at a ratio of 17.7: 1 through extrusion process. To identify the effects of heat treatment, T6 heat treatment (515 °C/1 h, water quenching, and then 175 °C/10 h) was performed. Microstructural observation identified Si phases aligned in the extrusion direction in both extruded alloy (F) and heat treated alloy (T6). The average grain size of F alloy was 8.15 °C, and that of T6 alloy was 8.22 °C. Both alloys were composed of Al matrix, Si, Al₂Cu, Al₃Ni and AlFeSi phases. As T6 heat treatment was applied, Al₂Cu phases became more finely and evenly distributed. Tensile results confirmed that yield strength increased from 119.0 MPa to 329.0 MPa, ultimate tensile strength increased from 226.8 MPa to 391.4 MPa, and the elongation decreased from 16.1% to 5.0% as T6 heat treatment was applied. High-cycle fatigue results represented F alloy’s fatigue limit as 185 MPa and T6 alloy’s fatigue limit as 275 MPa, indicating that high-cycle fatigue properties increased significantly as heat treatment was conducted. Through tensile and fatigue fracture surface analysis, this study considered the deformation behaviors of extruded and heat treated Al-Si alloys in relation to their microstructures.     

Phase continuity in high temperature Mo–Si–B alloys: A FIB-Tomography Study

The microstructure of mechanically alloyed Mo–Si–B materials of different compositions has been studied by X-ray diffraction and FIB-tomography. Three different phases were found in all alloys: α-Mo solid solution, T2-phase (Mo₅SiB₂-type) and A15-phase (Mo₃Si). The Mo–6Si–5B and Mo–9Si–8B (at%) alloys reveal a continuous morphology of the α-Mo phase. In Mo–9Si–8B the α-Mo phase is distributed more homogeneously compared to the Mo–6Si–5B alloy. In contrast, Mo–13Si–12B does not possess a continuous α-Mo phase. The consequences for the mechanical properties and oxidation resistance are discussed.