Tungsten heavy alloy: deformation texture and recrystallization of tungsten particles

Sintered tungsten heavy alloy (90W, 7Ni, 3Fe) has been deformed in different ways and heat treated at 800–1100 °C. The texture and dislocation density of the tungsten particles were determined as well as the effect of the heat treatment on recovery and recrystallization. A 1 1 0 deformation texture of the tungsten particles was found using X-ray diffraction. Formation of dislocation cells and subgrains was found to occur during the heat treatment as well as recrystallization by grain boundary migration. A model for the recrystallization of particles by grain boundary motion in a deformed heavy alloy is presented.     

Aging transformation in Cu-3.2Ni-0.75Si alloy

1　INTRODUCTIONHavinghighstrengthand goodelectricalandthermalconductivities,copperalloysareusedinanumberofengineeringapplications ,suchaselectricresistanceweldingelectrodes ,thelinertubeofcon tinuouscastingcrystallizer ,integratedcircuitleadframe ,aerialconductorofelectriclocomotive .Therepresentativeprecipitation hardenablecopper baseal loysfortheapplicationsareCu Cr[1] ,Cu Cr Zr[2 ] ,Cu Fe Cr[3] ,Cu Ni Si[4 6 ] etc .PrecipitationinCu Cr ,Cu Cr Zr ,Cu Fe Palloysusuallystartsfromth…     

钨丝增强铜基复合材料超高速撞击后的微观损伤

通过渗流铸造的方法将Cu78Al10Fe6Ni6合金与钨丝复合制备出Wf/Cu78Al10Fe6Ni6复合材料。采用二级轻气炮进行Wf/Cu78Al10Fe6Ni6复合材料弹体超高速侵彻混凝土靶的实验,实验速度为2.4km/s。借助透射电镜对侵彻后剩余弹体的微观组织进行观察,由于侵彻过程中高温高压的作用,剩余弹体的不同区域出现了不同的微观组织,从弹头到弹尾依次出现了非晶组织、再结晶、孪晶、层错和位错。非晶组织是由于弹体在撞击过程中产生的高温使基体铜合金发生了熔化而后又快速凝固产生的,再结晶组织是由于基体铜发生了旋转动态再结晶而产生的,孪晶、层错、高密度位错是由于弹体在侵彻过程中受到大的动载荷冲击发生严重塑性变形而产生的。     

Effects of Fe content on microstructure and properties of Cu–Fe alloy

Cu–Fe alloys with different Fe contents were prepared by vacuum hot pressing. After hot rolling and aging treatment, the effects of Fe content on microstructure, mechanical properties and electrical conductivity of Cu–Fe alloys were studied. The results show that, when w(Fe)<60%, the dynamic recrystallization extent of both Cu phase and Fe phase increases. When w(Fe)≥60%, Cu phase is uniformly distributed into the Fe phase and the deformation of alloy is more uniform. With the increase of the Fe content, the tensile strength of Cu–5wt.%Fe alloy increases from 305 MPa to 736 MPa of Cu–70wt.%Fe alloy, the elongation decreases from 23% to 17% and the electrical conductivity decreases from 31%IACS to 19%IACS. These results provide a guidance for the composition and processing design of Cu–Fe alloys.     

Microstructure and properties of Cu–2.8Ni–0.6Si alloy

The phase transformation behavior and heat treatment response of Cu-2.8Ni-0.6Si (wt%) alloy subjected to different heat treatments were studied by X-ray diffraction, transmission electron microscopy observation, and measurement of hardness and electrical conductivity. The variation of hardness and electrical conductivity of the alloy was measured as a function of aging time. On aging at the temperature below TR (500-550°C) in Cu-2.8Ni-0.6Si alloy, the transformation undergoes spinodal decomposition, DO22 ordering, and d-Ni2Si phase. On aging at the temperature above TR (500-550 °C), the transformation products were precipitations of d-Ni2Si. The free energy versus composition curves were employed to explain the microstructure observations.     

Cu-Ni-Fe双相合金在800～900℃的低氧压氧化

研究了经自发分解产生的Cu 30Ni 2 5Fe(摩尔分数 ,% )双相合金在 80 0～ 90 0℃于低氧分压 (只有Fe可被氧化 )条件下的氧化行为。该合金的氧化动力学遵循抛物线规律 ,相同氧化条件下 ,其氧化速率低于纯Fe和二元Cu 2 5Fe合金。氧化膜包括Fe3O4外层和FeO的内氧化物颗粒 ,并且FeO均匀分布在Cu Ni固溶体上 ,与合金两相的初始分布没有联系 ,而内氧化带前沿合金中出现贫Fe的Cu Ni固溶体单相层。讨论了二元 /三元双相合金与单相合金由互固溶度引起的氧化行为差异 ,认为双相合金中难以发生最活泼组元的单一外氧化是由于组元在基体中的扩散受到双相强烈限制的结果。     

涂层导体用Ni9W合金基带再结晶及强立方织构的形成研究

采用X射线四环衍射技术对比分析了通过冷轧和轧制中间热处理制备的2种Ni-9.3at%W(Ni9W)合金基带的轧制织构和再结晶织构,研究了不同Ni9W合金基带在热处理过程中轧制织构向再结晶织构的演变。其次,采用背散射电子衍射(EBSD)技术对以上2种Ni9W合金基带的微观组织和立方织构进行了表征。结果表明,与传统冷轧Ni9W合金基带的轧制织构相比,经轧制中间热处理后其轧制织构中S取向和Copper取向的含量增加、Brass取向的含量减少,使其轧制织构的类型介于Brass型轧制织构与Copper型轧制织构之间。2种Ni9W合金基带经低温回复后,其轧制织构含量均有一定的增加;另外,再结晶过程中轧制织构的含量均迅速降低,但立方取向的含量并没有明显增加,而是出现大量的随机取向,Ni9W的再结晶具有了连续再结晶的特征,这也是导致Ni9W合金基带较难形成立方织构的一个主要原因。虽然经过轧制中间热处理后Ni9W合金基带在初始再结晶完成后并没有形成一定强度的立方织构,但其立方取向的含量仍然能在进一步热处理过程中通过立方取向晶粒的长大而得到加强。最后,采用轧制中间热处理制备的Ni9W合金基带经两步高温热处理后其立方织构的含量达到84.5%(15°)。     

Ni-Ti合金时效早期相变规律的研究

通过ＴＥＭ分析对Ｎｉ１０％Ｔｉ（％，质量分数，下同）合金时效早期相变过程的研究表明Ｎｉ１０％Ｔｉ合金过饱和固溶体先通过调幅分解机理分解为贫、富溶质区；随后富溶质区发生有序化，最后形成Ｌ１２型有序相Ｎｉ３Ｔｉ。同时发现，淬冷抑制了该合金固溶体的相分解过程。ＮｉＴｉ合金时效相变过程中存在调幅分解与有序化两种失稳模式共存现象。     

Evolution of microstructure,hardness, and corrosion properties of high-entropy Al0.5CoCrFeNi alloy

In this study, we investigate the microstructure, hardness, and corrosion properties of as-cast Al_0.5CoCrFeNi alloy as well as Al_0.5CoCrFeNi alloys aged at temperatures of 350 °C, 500 °C, 650 °C, 800 °C, and 950 °C for 24 h. The microstructures of the various specimens are investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe X-ray microanalysis (EPMA). The results show that the microstructure of as-cast Al_0.5CoCrFeNi comprises an FCC solid solution matrix and droplet-shaped phases (Al–Ni rich phases). At aging temperatures of between 350 and 950 °C, the alloy microstructure comprises an FCC + BCC solid solution with a matrix, droplet-shaped phases (Al–Ni rich phase), wall-shaped phases, and needle-shaped phases (Al–(Ni, Co, Cr, Fe) phase). The aging process induces a spinodal decomposition reaction which reduces the amount of the Al–Ni rich phase in the aged microstructure and increases the amount of the Al–(Ni, Co, Cr, Fe) phase. The hardness of the Al_0.5CoCrFeNi alloy increases after aging. The optimal hardness is obtained at aging temperatures in the range 350–800 °C, and the hardening effect decreases at higher temperatures. Both the as-cast and aged specimens are considerably corroded when immersed in a 3.5% NaCl solution because of the segregation of the Al–Ni rich phase precipitate formed in the FCC matrix. Cl^? ions preferentially attack the Al–Ni rich phase, which is a sensitive zone exhibiting an appreciable potential difference, with consequent galvanic action.     

形变Cu-4Al合金再结晶动力学

测试了Cu-4Al合金经50％变形后在不同温度下再结晶动力学曲线，并根据公式G＝G0exp(-Q/RT)计算出再结晶激活能。     

Ni、Fe合金化及时效时间对锰铜基阻尼合金相变行为的影响

使用真空感应炉制备了Mn-20Cu、Mn-20Cu-5Ni、Mn-20Cu-5Ni-2Fe三种不同成分梯度的合金,利用动态机械分析仪测量了弹性模量及内耗与温度之间的关系,以研究化学成分及时效时间对合金反铁磁转变及马氏体相变的影响。结果表明,合金的相变特征温度和时效时间的平方根正相关,添加的合金元素通过影响调幅分解过程中溶质原子的扩散从而对特征温度发生作用,描述振荡应力和相界面之间耦合强度的l值是反映阻尼合金材料的关键因素之一。     

Relationship of corrosion product films and recrystallization of 70Cu‐30Ni alloy

The corrosion and microstructure of 70Cu‐30Ni alloy plates and commercial tubes were investigated by processing, electrochemical technique and seawater exposure as well as optical microscopy, SEM, EDX and AES. The alloy plate with incomplete recrystallization, consisting of deformed and recrystallized grains, demonstrates loose and porous outer layers and denickelification in the inner layers for its corrosion product films, whereas the recrystallized alloy plate forms smooth and compact corrosion product films rich in nickel after immersion in seawater for 3 and 6 months. The incompletely recrystallized alloy tube keeps an active state and the recrystallized tube has a passive zone in the anodic polarization curve in 3.5% sodium chloride. Furthermore, the former shows loose and thick corrosion product films, which are of denickelification in the inner layer and contain a significant amount of seawater species in the outer layer, and on the surface of the latter are thin uniform and compact corrosion product films containing a Ni enrichment zone which becomes richer in Ni and wider with increasing immersion time. It is found that intergranular corrosion proceeds along the boundaries of deformed and recrystallized grains, and it is ascribed to electrochemical cells built for the reason of potential difference between the two kinds of grains.     

微量Er在高强Al-Zn-Mg-Cu合金中的存在形式及其“遗传效应”

采用铁模铸造制备Al-Zn-Mg-Cu及Al-Zn-Mg-Cu-0.15% Er两种合金铸锭。利用光学显微镜（OM）、扫描电镜（SEM）及能谱分析（EDS）、差热分析（DSC）、透射电镜（TEM）、X射线衍射分析（XRD）和常温拉伸等方法研究了Er元素在Al-Zn-Mg-Cu合金铸态组织、均匀化态组织、变形组织以及时效态组织中的存在形式、作用机理以及其对合金室温拉伸性能的影响。研究结果表明： 微量Er元素对Al-Zn-Mg-Cu合金铸态组织有一定细化作用,但这种作用较为有限。Er在合金中主要以三元Al8Cu4Er相的形式存在,该相在合金凝固过程中形成并偏聚在晶界附近,常出现在共晶网状结构之间。此外,还有少量的Er生成了细小Al3Er粒子。Al8Cu4Er相熔点约为573.8°C,为难溶硬脆第二相,在合金变形过程中易破碎从而会导致裂纹萌生或成为粒子诱发再结晶形核的核心,最终会对合金的综合力学性能产生不利的影响。     

Phase Separation Process at Early Aging Stage of Ni42CrTiAl

Phase separation process of Ni42CrTiAl alloy aged at various temperatures was studied by means of transmission electron microscope and X-ray diffraction. It was concluded that the temperature of spinodal decomposition is 500℃. And the solid solution break into the lean and the rich areas, moreover the rich solute areas would have ordering arrangement to form ordering phase.     

一种Ni3Al基单晶高温合金的再结晶动力学及组织变化（英文）

研究了一种Ni3Al基单晶高温合金的再结晶动力学及组织变化,解释了造成枝晶干和枝晶间再结晶行为不一致的原因。单晶合金经表面喷砂处理,再在惰性气氛中,于1280℃下退火不同时间形成再结晶晶粒。研究发现：枝晶干再结晶层厚度大于枝晶间再结晶厚度,枝晶干再结晶速率快于枝晶间再结晶速率。在退火过程中,枝晶间有Y-NiMo相析出,且强烈抑制再结晶。然而,随着时间的延长Y-NiMo析出相逐渐溶解,且抑制再结晶的作用逐渐减弱,最终,枝晶干再结晶层厚度仍然大于枝晶间再结晶厚度。     

溅射靶材用Cr20Ni80合金管材的微观组织与再结晶退火

对溅射靶材用Cr20Ni80合金冷轧管材的微观组织和再结晶退火工艺进行了研究。首先观察了冷轧管材轴向与径向的微观组织变化;其次利用JMatPro计算了Cr20Ni80合金的相图,并设计了再结晶退火工艺;最后对冷轧管材进行了再结晶退火试验,表征了退火后管材的微观组织、晶粒尺寸和硬度。结果表明,冷轧管材沿轴向均为拉长晶,且存在大量孪晶;管材沿径向的微观组织中晶粒尺寸因形变量的增大而减小;当再结晶退火温度为690 ℃时,冷轧管材试样已开始发生再结晶;790 ℃×30 min时,形变晶粒已完全再结晶,平均晶粒尺寸为24.1 μm,为最优再结晶退火工艺;当退火温度进一步升高、保温时间进一步延长时,再结晶晶粒逐渐长大;试样的硬度随退火温度的升高而减小。     

固溶制度对1933铝合金自由锻件组织和力学性能的影响

采用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射和室温拉伸研究固溶制度对1933铝合金自由锻件组织和力学性能的影响.结果表明:由于Al_3Zr粒子对晶界的钉扎作用,在470 ℃以下固溶时,合金的再结晶程度很低(＜15%);随着固溶温度升高,再结晶程度逐渐上升;510 ℃固溶时,合金的再结晶程度显著增大(约为48%);1933铝合金锻件中第二相主要有Al_7Cu_2Fe相和η相;合金经470 ℃固溶60 min后,η相溶解比较充分,此后随温度升高或时间延长第二相变化不大;合金的最佳固溶制度为470 ℃、60 min,在此条件下合金具有最好的力学性能.     

Effects of Ni content on microstructure and properties of aged Cu−0.4Be alloy

The effects of Ni content (0?2.10 wt.%) on the precipitated phase, strength and electrical conductivity of Cu?0.4wt.%Be alloy were investigated, and the influencing mechanism was analyzed. The results showed that the addition of Ni promoted the precipitation of strengthening phase in the alloy and remarkably enhanced the strengthening effect. When the Ni content was increased from 0 to 2.10 wt.%, the strength of the aged alloy initially increased and then decreased, and approached the maximum when the Ni content was 1.50 wt.%. The peak-aging parameters of the alloy containing 1.50 wt.% Ni were the aging temperature of 400 °C and the aging time of 60 min, where the tensile strength and yield strength of the aged alloy were 611 and 565 MPa, respectively, which were 2.8 times and 6.1 times those of the alloy without Ni. The electrical conductivity of the alloy with Ni increased with the aging time, and decreased with the increase of Ni content. With an increase of the aging time at 400 °C, phase transition sequence of the Cu?0.4Be?1.5Ni alloy was γ″ phase →γ′ phase →γ phase. For the aging time of 60 min, a large number of dispersed nano-scale coherent γ″ phase and γ′ phase formed in the alloy with a remarkable strengthening effect, which was mainly responsible for the high strength of the alloy.     

Al-Zn-Ni-Mg-Cu变形铝合金的共晶强化效应

在Al-Zn-Mg-Cu变形铝合金中加入质量分数3%～5%的Ni元素,通过共晶反应形成了大量的Al_3Ni相,除MgZn_2相时效强化以外还增加了Al_3Ni相的弥散强化作用。Ni含量的增加既改善了Al-Zn-Mg-Cu变形铝合金的铸造性能和可焊性,又提高了抗拉强度和屈服强度。Al-Zn-Ni-Mg-Cu铝合金较佳的成分为Al-5.6Zn-3.5Ni-2Mg-1Cu,其抗拉强度、屈服强度和断后伸长率分别为650 MPa、572 MPa和7.5%,焊接接头的抗拉强度和断后伸长率分别为323 MPa、2%。随着强度的增加,Al_3Ni相由界面撕裂转变为自身断裂,Ni含量的增加提高了Al_3Ni的强化效果,但不宜超过共晶点。降低Al_3Ni相的长径比能抑制Al_3Ni相的自身断裂,Al_3Ni相的均匀分布能阻碍再结晶晶粒的异常长大。     

激光超快速加热下冷轧Cu30%Zn合金的再结晶织构

加热速度对冷变形金属的再结晶织构具有很大影响。利用激光超快速加热方法对冷轧Ｃｕ３０ ％ Ｚｎ 合金进行了再结晶处理。实验结果表明, 其织构转变过程与普通加热时差别很大。对于冷轧７０ ％ 和８５ ％ 的样品, 完全再结晶时的织构均很漫散, 伴随着再结晶晶粒长大, 两种样品中的织构特征仍然保持漫散趋势。