EFFECTS OF HEAT TREATMENT ON TENSILE PROPERTIES AND SHAPE MEMORY EFFECTS OF Ni-Ti-Nb ALLOY

ＥＦＦＥＣＴＳＯＦＨＥＡＴＴＲＥＡＴＭＥＮＴＯＮＴＥＮＳＩＬＥＰＲＯＰＥＲＴＩＥＳＡＮＤＳＨＡＰＥＭＥＭＯＲＹＥＦＦＥＣＴＳＯＦＮｉＴｉＮｂＡＬＬＯＹ①ＺｈｅｎｇＹｕｆｅｎｇ，ＣａｉＷｅｉ，ＬｕｏＹｉｃｈｕｎ，ＺｈａｏＬｉａｎｃｈｅｎｇＳｃｈｏｏ...     

EFFECTS OF TEMPERATURE TREATMENT ON MICROSTRUCTURE AND PROPERTIES OF ZA27 ALLOY

ＥＦＦＥＣＴＳＯＦＴＥＭＰＥＲＡＴＵＲＥＴＲＥＡＴＭＥＮＴＯＮＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＰＲＯＰＥＲＴＩＥＳＯＦＺＡ２７ＡＬＬＯＹ￥Ｇｅｎｇ，Ｈａｏｒａｎ；Ｇｅｎｇ，Ｇｕｉｌｉ；Ｇａｏ，Ｘｉｑｉ；Ｍａ，Ｊｉａｊｉ（ＤｅｐａｒｔｍｅｎｔｏｆＭａ...     

EFFECT OF HEAT TREATMENT ON INTERNAL FRICTION OF GRAIN BOUNDARY IN 2091 Al-Li ALLOY

ＥＦＦＥＣＴＯＦＨＥＡＴＴＲＥＡＴＭＥＮＴＯＮＩＮＴＥＲＮＡＬＦＲＩＣＴＩＯＮＯＦＧＲＡＩＮＢＯＵＮＤＡＲＹＩＮ２０９１ＡｌＬｉＡＬＬＯＹＳｕｎＤｏｎｇｌｉ，ＹａｎｇＤｅｚｈｕａｎｇ，ＹａｎｇＺｈｅｎｇｙａｏＳｃｈｏｏｌｏｆＭａｔｅｒｉａｌｓＳｃｉ...     

EFFECTS OF TWO－STEP HEAT－TREATMENT ON MICROSTRUCTURE AND PROPERTIES OF TiAl INTERMETALLICS

ＥＦＦＥＣＴＳＯＦＴＷＯ－ＳＴＥＰＨＥＡＴ－ＴＲＥＡＴＭＥＮＴＯＮＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＰＲＯＰＥＲＴＩＥＳＯＦＴｉＡｌＩＮＴＥＲＭＥＴＡＬＬＩＣＳ￥Ｋｏｎｇ，Ｇａｏｎｉｎｇ；Ｈｕａｎｇ，Ｂａｉｙｕｎ；Ｑｕ，Ｘｕａｎｈｕｉ；Ｌｅｉ，Ｃｈａ...     

FORMATION OF GRADIENT COATING OF Fe-BASED ALLOY WITH RARE EARTHS BY PLASMA SURFACING

A gradient coating of Fe-based alloy was manufactured with rare earths (RE) by plasma surfacing on Q235 steel substrate. The coatings were studied by using X-ray diffraction (XRD), scanning electron microscope (SEM), differential thermal analyzer (DTA), and electron probe micro-analyzer (EPMA). The results show that the phases of the two kinds of coatings(with and without RE) both include α-Fe, Fe7C3， Fe3C, Cr2B, Fe2B and FeB. The microstructure of F314 coating is mainly hypereutectic, the pro-phases Cr7C3 and Cr2B are loose, crassi, spiculate and contain microcracks. The brittleness of the coating is high, and the average hardness is 787 HV. When 0.8wt% RE was added into the F314 alloy, the microstructure varied from hypoeutectic to hypereutectic continuously, The hardness appears as gradient distribution with the highest value of 773 HV, meanwhile, the brittleness decreases significantly. The formation of gradient structure depends on the fallowing factors: (i) the conversion of RE. The addition of RE lowers the elements point and Fe-C eutectic temperature, thus the base metal melting acutely. (ii) the heating of plasma arc.Graded temperature results in directional solidification, thus the gradient structure forms easily. The main reasons for the hardness decrease with RE addition in the alloy are the ratio of hard phase lowering and the hardness of the hard phase decreasing.     

INFLUENCE OF HEAT TREATMENT PROCESSES ON MECHANICAL PROPERTIES OF ACu－Ni－AI－Ti ALLOY

ＩＮＦＬＵＥＮＣＥＯＦＨＥＡＴＴＲＥＡＴＭＥＮＴＰＲＯＣＥＳＳＥＳＯＮＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＯＦＡＣｕ－Ｎｉ－ＡＩ－ＴｉＡＬＬＯＹＩＮＦＬＵＥＮＣＥＯＦＨＥＡＴＴＲＥＡＴＭＥＮＴＰＲＯＣＥＳＳＥＳＯＮＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲ...     

EFFECT OF SOLUTION TREATMENT IN AN ELECTRIC FIELD ON MECHANICAL PROPERTIES AND MICROSTRUCTURE OF 2091 Al—Li ALLOY

Solution treatment of 20% Al-Li alloy in an electric field has been studied The results show that it increases the solubility of elements and accelerates the nucleation ofT_1-phaseand promotes the formation of the precipitation free zones(PFZ), and increases the strength and decreases the plasticity ofthe allov.     

EFFECT OF VACUUM HEAT TREATMENT ON OXIDATION BEHAVIOR OF SPUTTERED NiCrAlY COATING

A bond coat for thermal barrier coating (TBC), NiCrAlY coating, is subjected to vac-uum heat treatment in order to remove internal stress before ceramic top coat is de-posited. The effect of vacuum heat treatment on the oxidation behavior of the sputtered NiCrAlY coating has been investigated. The as-sputtered NiCrAlY coating consists of γ-Ni and b-NiAl phases. After vacuum heat treatment, the sputtered NiCrAlY coating mainly consists of γ'-Ni3Al, β-NiAl, γ-Ni, and trace of α-Al2O3 phases. The isothermal oxidation of sputtered NiCrAlY coating with and without vacuum heat treatment has been performed at 1000℃. It is shown that a-Al2O3 formed during vacuum heat treatment acts as nuclei for the formation of a-Al2O3, and the protective a-Al2O3 scale is formed more rapidly on the vacuum heat treated NiCrAlY coating than that formed on the untreated coating. Also the a-Al2O3 scale has a better adherence to the vacuum heat treated NiCrAlY coating. Therefore the vacuum heat treatment improves the oxidation     

INFLUENCE OF HEAT TREATMENT ON THE MECHANICAL PROPERTIES OF RE Al-5.0Mg-0.6Cu ALLOY SHEET FOR AUTOMOBIL BODIES

The influences of solution temperature,time in solution and quenching rate on the mechanical properties ofRE Al-5.0Mg-0,6Cu(wt.-%)alloy sheets for automobile bodies have been studied.The results show the re-quirements for heat treatments for the alloy sheets were not harsh.Therefore this alloy sheets are easy to produceon an industrial scale.The experiments indicate that there exists slight age hardening in the alloy.The typicalmicrostructures of the alloy have also been analysed.     

EFFECTS OF Zn CONCENTRATION ON WETTABILITY OF Sn-Zn ALLOY ON Cu AND ON THE INTERFACIAL MICROSTRUCTURE BETWEEN Sn-Zn ALLOY AND Cu

The potential of using a hypoeutectic, instead of eutectic, Sn-Zn alloy as a lead-free solder has been discussed. The nonequilibrium melting behaviors of a series of Sn-Zn alloys were examined by differential thermal analysis. It was found that at a heating rate of 5℃/min, Sn-6.SZn exhibited no melting range. Dipping and spreading tests were carried out to characterize the wettability of Sn-Zn alloys on Cu. Both tests exhibited that Sn-6.5Zn has significantly better wettability on Cu than Sn-9Zn. The reaction layers formed during the spreading tests were examined. When the Zn concentration fell between 2.5wt%-9wt%, two reaction layers were formed at the interface, a thick and flat Cu5Zn8 adjacent to Cu and a thin and irregular Cu-Zn-Sn layer adjacent to the alloy. Only a Cu0Sn5 layer was formed when the Zn concentration decreased to 0.5wt%. The total thickness of the reaction layer（s） between the alloy and Cu was found to increase linearly with the Zn concentration.     

稀土元素和固溶处理对Al阳极电化学性能的影响

对Al-Zn-In-Sn-Mg和Al-Zn-In-Sn-Mg-RE 2种Al合金 阳极进行固溶处理，测定了经固溶处理和未经固溶处理的阳极在20℃和65℃的3%NaCl溶液中 的电化学性能 .结果表明,高温下Al阳极电流效率普遍下降，腐蚀变得不均匀;添加RE的固 溶处理阳极在65℃时性能优良；固溶处理可改善Al阳极在高温介质中的性能.讨论了RE及固 溶处理对高温介质中Al阳极性能的影响.     

稀土元素对低合金耐磨铸铁耐磨性的影响

从改变共晶碳化物形貌的角度研究了稀土元素对低合金耐磨铸铁耐磨性的影响。结果表明,稀土元 素能改善共晶碳化物的形状,提高其耐磨性,尤其稀土变质后再经950℃×3h正火处理后效果更显著。     

Mg-9Al合金铸造凝固模型

在热力学基础上建立了Mg-9Al合金的铸造凝固模型。考察了Mg-9Al合金在铸造凝固条件下的固相分数、体积收缩和微观偏析行为。模拟结果表明，在本凝固条件下，合金实际凝固结束温度在共晶温度附近而不是固相线温度。凝固过程中的体积变化也是非线性的。在凝固初始阶段收缩较大；当剩余液相到达共晶成分时收缩较小。在凝固后期由于发生共晶转变，产生剧烈的凝固收缩。模拟结果与实验测试相符合。     

EFFECTS OF HEAT TREATMENT ON THE MICROSTRUCTURE OF Cu-Zn-Al (RE) SHAPE MEMORY ALLOYS

1. Introduction Cu-Zn-Al shape memory alloys have extensive application prospects because of their unique properties and low cost. However, some elements have to he added into Cu-Zn- Al shape memory alloys in order to refine their grains and to improve their mechanical properties. Some works indicated that adding rare earth (RE) elements or mixed RE (La+Ce) could improve the related properties remarkably[13]. The effects of RE addition are as the following: (1) refining grains of the al…     

热处理工艺对一种新型铸造镍基高温合金的组织和性能影响

通过改变固溶热处理温度、保温时间和固溶后冷却方式,研究了不同固溶热处理工艺对一种新型铸造高温合金组织和性能的影响.结果表明,将合金在不同温度固溶处理2 h后空冷,合金在760℃,660 MPa和980℃,180 MPa条件下的持久寿命随热处理温度的升高先升高而后降低;固溶处理温度为1220℃时,760℃,660 MPa条件下的持久寿命达到最高;固溶处理温度为1180℃时,980℃,180 MPa条件下的持久寿命最高;当热处理温度从1120℃升高到1220℃时,拉伸强度随温度升高而增加,继续升温到1240℃,拉伸强度下降.当固溶热处理温度为1120℃,处理时间在2-8 h范围内变化时,合金在760℃,660 MPa条件下的持久寿命随时间延长而降低,而在980℃,180 MPa条件下的持久寿命随处理时间延长而升高;当热处理时间为2和4 h时,拉伸强度较高;延长到6和8 h时,拉伸强度下降.当冷却方式不同时,合金持久性能也发生变化.γ′相和γ/γ′共晶组织在尺寸、形态、分布和数量上的变化是导致合金力学性能变化的关键因素.     

A NEW HEAT TREATMENT PROCESSING FOR TiAl BASED ALLOY

ＡＮＥＷＨＥＡＴＴＲＥＡＴＭＥＮＴＰＲＯＣＥＳＳＩＮＧＦＯＲＴｉＡｌＢＡＳＥＤＡＬＬＯＹ￥ＨｅＹｕｅｈｕｉ；ＨｕａｎｇＢａｉｙｕｎ；ＬｉｕＹｏｎｇ；ＬｉｕＹｅｘｉａｎｇ（ＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆｐｏｗｄｅｒＭｅｔａｌｌｕｒｇｙＣｅｎｔｒ...     

添加稀土引致的磷化膜变化与促进机制

用能谱与SEM分析，发现加入稀土硝酸盐(REN)后明显提高了无定形晶体Zn2Fe(PO4)2在磷化膜表面的覆盖率，而使得膜的耐蚀性能提高.此时膜内相关元素含量比例发生了变化：P增大,Zn减小，可见磷对膜耐蚀性的贡献比锌大.讨论认为，稀土硝酸盐是一个有良好载氧能力的催化剂，具有良好的成核促进作用和阴极去极化作用，从而能加速磷化并使膜的耐腐蚀性能提高. 