时效对Cu—Cr—Zr合金显微硬度及导电率的影响

探讨了时效工艺及形变量对Cu—0.3Cr—0．15Zr合金显微硬度及导电率的影响。结果表明，合金经920℃固溶处理后在420℃及460℃时效可分别达到较好的硬度和导电率，分别达183HV和68％IACS；时效前对合金加以适当冷变形可加速合金时效析出过程。影响合金导电率的主要因素是基体中固溶元素的含量，含量越高，导电率越低，反之则越高。而时效前冷变形可以增加合金内部位错等缺陷的数量，加速了合金第二相的析出。     

FeCrNiMnZr_x高熵合金组织与力学性能研究

Fe_(27)Mn_(27)Ni_(28)Cr_(18)高熵合金具有优异的耐腐蚀性和抗辐照性,但其屈服强度较低。为提高合金的强度,采用真空电弧熔炼炉制备了FeCrNiMnZr_x(x=0,0.02,0.03,0.07)高熵合金,并对其组织及力学性能进行表征分析。研究结果表明:FeCrNiMn合金的铸态组织由富Ni、Mn的FCC基体和富Cr的片状BCC相组成。当添加相对含量x=0.02的Zr元素时,FeCrNiMnZr_(0.02)合金中富Cr的BCC相呈短细条状或花边状,有少量小片状或短条状的Ni_(11)Zr_9化合物析出,合金强度和硬度同时升高,具有最佳的综合力学性能。随着Zr添加量的进一步增加,合金中富Cr的BCC相逐渐减少,而枝晶间析出的Ni_(11)Zr_9化合物量逐渐增多,形态也变为长链条状乃至完全网状,合金的屈服强度和硬度升高,但断后延伸率大幅下降。断口分析发现,随Zr含量增加,合金的断裂机制由以韧窝为主的韧性断裂逐渐转变为以解理台阶为主的脆性断裂。     

Mg-8Zn-4Al-0.3Mn-xRE合金的时效析出过程及其动力学

采用金相显微分析和DSC分析了Mg-8Zn-4A1-0．3Mn-x RE含金时效析出过程及其动力学，结果表明，未添加RE元素的Mg-8Zn-4A1-0．3Mn合金的时效析出过程为：过饱和固溶体→细小弥散析出相→再结晶软化和析出相的聚集长大；添加RE元素的Mg-8Zn-4A1-0．3Mn合金的时效析出过程为：过饱和固溶体→细小弥散析出相→析出相的聚集长大．人工时效后，与未加RE的合金相比，合金2，3，4显微硬度峰值提高分别达5．6％，9％，13．4％；随着RE元素含量的增加，合金的析出相形成激活能呈逐渐增大的变化规律．     

热处理改善ZA27MuSi合金组织性能的机理

研究了固溶时效工艺参数对ＺＡ２７ＭｎＳｉ合金的冲击值、金相组织和断口形貌的作用规律，认为该合金的固溶过程包括枝晶成分均匀化、化合物溶解、非平衡共晶组织的扩散消失和晶粒粗化；时效过程主要包括α相的共析分解、合金元素的聚集和化合物析出长大以及组织粗化．结果表明，经１８０℃或２７０℃固溶、自然时效，ＺＡ２７ＭｎＳｉ合金的冲击值可由铸态的１５Ｊ／ｃｍ提高到４１０～４６Ｊ／ｃｍ．     

时效对Cu-1．ONi-0．25Si-0．10Zn合金硬度与导电率的影响

分析了时效与冷变形对Cu-1．0Ni-0．25Si-0．10Zn合金的硬度与导电率的影响规律，结果表明：合金经850℃固溶处理后在450℃时效时，第二相呈弥散分布，表现出较大的稳定性，在525℃时效时第二相的析出速度较快，时效后可获得较高的导电率；时效前的冷变形可以加速时效析出过程，在时效的初期尤为明显。合金采用分级时效工艺处理后，可得到高的硬度(HV171)和较高的导电率(59．5％IACS)。     

AZ91D合金的时效分析

通过光学显微观察、扫描电镜等实验手段对AZ91D镁合金在时效处理过程中组织和性能的变化规律进行了研究,结果表明:时效析出相可大大增加合金的硬度值,但当析出达到一定程度后,合金硬度稳定在较高的水平上;时效可使沉淀相大量析出,强化效果明显,可显著提高材料的性能.     

时效对蒙耐尔（MONEL）合金组织及硬度的影响

合金在不同时效温度，不同时效时间下进行时效处理时，在硬度上都将出现一个最大峰值，并随时效时间的延长，硬度值逐渐下降，其变化的主要原因是在时效过程中有γ沉淀相析出，而γ沉淀相的大小与时效温度，时效时间有关。合金的强化主要来源于γ沉淀相对运动位错的阻碍作用。     

GH9158铁基高温合金析出相分析

目的　研究合金元素在 GH91 58合金各析出相中的分配及浓度的变化规律 .方法　采用电解萃取相分析方法 .结果　测定和计算了不同时效温度下析出相的类型、数量、组成结构 .结论　析出相 M6 C,Laves在 ( 72 0～ 82 0 )℃时效过程中是稳定的     

时效温度对铝锂合金组织及性能影响研究

通过金相显微镜、扫描电镜和硬度等实验手段研究时效温度对Al-Li-Cu-Mg合金微观组织及其力学性能的影响,结果表明,合金中的强化相主要有δ′(Al_2Li)相、T_1(Al_2CuLi)相和θ′(Al_2Cu)相。在150℃时析出大量δ′相和少量T_1相;随着时效温度的升高,在165℃以上主要为大量T_1相,少量θ′相和δ′相。硬度分析表明,时效温度高于165℃时,T_1相与δ′相对合金产生协同强化作用。     

时效对Mg-7Gd-4Y-0.6Zn-0.6Zr合金显微组织及硬度的影响

为了提高Mg合金的强韧性和抗高温性能.文中通过显微硬度测试、差示扫描量热仪及透射电镜分析,研究了挤压Mg-7Gd-4Y-0.6Zn-0.6Zr系镁合金的显微硬度及时效析出相的结构.结果表明:钆的添加增强了Mg-Gd-Y合金的时效硬化效果,对合金时效硬化的总体规律无明显影响.透射电镜分析发现具有DO19超点阵的β″和斜方晶体β′相在合金时效硬化阶段析出,提高了合金硬度.在时效后期由于粗大的针片状1β相析出,使合金硬度下降.     

Microstructure and properties of W-15Cu alloys prepared by mechanical alloying and spark plasma sintering process

W-15Cu composite powders prepared by mechanical alloying （MA） of raw powders were consolidated by spark plasma sintering （SPS） process at temperature ranged 1 230-1 300 ℃ for 10 min and under a pressure of 30 MPa. By using high energy milling, particles containing very fine tungsten grains embedded in copper, called composite particles, could be produced. The W grains were homogeneously dispersed in copper phase, which was very important to obtain W-Cu alloy with high mechanical properties, fine and homogeneous microstructure. The microstructure and properties of W-15Cu alloys prepared by SPS processes at different temperature were researched. The results show that W-15Cu alloys consolidated by SPS can reach 99.6 % relative density, and transverse rupture strength （TRS） is 1 400.9 MPa, Rockwell C hardness （HRC） is 45.2, the thermal conductivity is 196 W/m-K at room temperature, the average grain size is less than 2 μm, and W-15Cu alloy with excellent properties, homogeneous and fine microstructure is obtained.     

Sn-Ag-xCu-Bi-Ni/Cu焊点界面IMC演变

为了研究低银无铅焊点界面金属间化合物(IMC)的形成与演变,以低银无铅焊点Sn-Ag-xCu-Bi-Ni/Cu为研究对象,研究了钎料中Cu质量分数对界面IMC厚度、形貌和成分的影响.实验结果表明,随着钎料中Cu质量分数的增加,回流焊后焊点IMC层厚度变薄,IMC晶粒尺寸增大,IMC晶粒形貌由颗粒状转变为棱柱状以及鹅卵石状,同时界面IMC成分发生由(Cu,Ni)6Sn5向Cu6Sn5的转变.高温时效后,界面IMC层厚度增长.当钎料中Cu质量分数超过1%时,时效后生成较厚的Cu3Sn化合物层,对焊点可靠性不利.钎料中Cu质量分数应控制在1%以下.     

A Cu-Cr alloy with nano and microscale Cr particles produced in a water-cooled copper mold

Microstructures have profound effects on the hardness and strength of Cu-Cr alloys. The microstructures of a Cu-Cr alloy cast in a water-cooled copper mold were studied in the present work. The scanning electron microscopy (SEM) results show that there are the copper matrix saturated with chromium, spherical precipitates of chromium separated from liquid phase during cooling before the initiation of so- lidification, and a eutectic phase in grain boundary areas. To investigate the effect of age-hardening tr...     

Effect of heat-treatment on the microstructures and mechanical properties of Mg-10Zn-5Al-0.1Sb-xCu magnesium alloy

The effects of the solution and aging treatment on microstructures and mechanical properties of the Mg-10Zn-5Al-0.1Sb-XCu cast magnesium alloys were investigated by brinell hardness measurement, scanning electron microscopy (SEM), energy spectrum analyzing apparatus and X-ray diffraction (XRD). The experimental results show that the strip-like τ-Mg₃₂ (Al, Zn)₄₉ phase is shown at the grain boundaries and Mg₂Cu phase become smaller, even granular after solution treatment at 350 °C for 24 h. By ageing treatment at 180 °C, the ternary strengthening phase (τ phase) precipitates gradually at or around grain boundary. With increasing aging time, the micro-hardness improves obviously and up to the maximum (105.9 HV) at aging time of 36 h. In addition, the tensile-strengths at room temperature and at an elevated temperature respectively reach 228 MPa and 176 MPa, which is increased by 20% and 10%, respectively.     

Microstructural features and properties of high-hardness and heat-resistant dispersion strengthened copper by reaction milling

The oxide dispersion strengthened copper alloys are attractive due to their excellent combination of thermal and electrical conductivities,high-temperature strength and microstructure stability.To date,the state-of-art to fabrication of them was the internal oxidation (IO) process.In this paper,alumina dispersion strengthened copper (ADSC) powders of nominal composition of Cu-2.5 vol%Al2O3 were produced by reaction milling (RM) process which was an in-situ gas-solid reaction process.The bulk ADSC alloys for electrical and mechanical properties investigation were obtained by sintering and thereafter hot extrusion.After the hot consolidation processes,the fully densified powder compacts can be obtained.The single γ-Al2O3 phase and profile broaden effects are evident in accordance with the results of X-ray diffraction (XRD);the HRB hardness of the ADSC can be as high as 95;the outcomes should be attributed to the pinning effect of nano γ-Al2O3 on dislocations and grain boundaries in the copper matrix.The electrical conductivity of the ADSC alloy is 55%IACS (International Annealing Copper Standard).The room temperature hardness of the hot consolidated material was approximately maintained after annealing for 1 h at 900 ℃ in hydrogen atmosphere.In terms of the above merits,the RM process to fabricating ADSC alloys is a promising method to improve heat resistance,hardness,electrical conductivity and wear resistance properties etc.     

时效处理对CuCrSnZn/SnAgCu钎料接头界面及剪切性能影响

为了探讨引线框架铜合金与无铅钎料钎焊接头界面性能,采用扫描电镜及万能材料实验机,分析了引线框架用CuCrSnZn合金与SnAgCu系无铅钎料钎焊接头,在160℃时效不同时间的过程中界面形貌及接头剪切性能的演变过程.结果表明,时效前,钎焊接头界面处形成了一层长针状的Cu6Sn5;不同时间时效处理后,接头界面IMC层厚度有不同程度的增加,Cu6Sn5变长变粗,逐渐离开界面进入钎料内部,靠近铜合金片材基体的一侧会出现极薄的一层Cu3Sn层.无铅钎料钎焊接头时效25h剪切强度可到27.3 MPa,其后逐渐降低.未时效、时效25 h和50 h断裂发生在钎料基体内部,时效至300 h,断裂位置向界面金属间化合物处转移,剪切断口断裂形式逐渐由韧性断裂向脆性断裂转变.     

时效对18Cr2Ni4WA钢性能的影响

通过对不同时效时间的处理 ,得到 18Cr2Ni4WA钢的冲击韧性值、硬度及晶粒度 ,并研究了它们之间的关系。     

含铜钢的等温时效过程

利用高分辨透射电镜观察了含铜高纯净钢等温时效过程中的微观组织形貌,借助维氏硬度计进行硬度测试.结果表明,随时效时间增加,试样硬度发生一系列变化,TEM观察分析发现,固溶态形成的有序畴在整个析出强化过程中起着重要作用.     

Precipitation behavior of B2—like particles in Fe—Cu binary alloy

The precipitation behavior in Fe-Cu binary alloy was investigated under transmission electron microscope(TEM) during aging at 650℃ for the time range of 100s to 300h,In addition to the zones with higher copper content and ε-Cu were observed,a metastable phase with B2-like structure was found in the early stage of the precipitation process,which is quite different from the equilibrium copper phase shown in the Fe-Cu binary phase diagram and has perfect coherent relationship to the α-Fe matrix.The appearance of B2-like structure is very important concerning the mechanism of aging strengthening effect and mechanical properties of corresponding engineering steels and alloys containing copper.     

Cu(Ⅱ)-CAS-en-CTMAB显色反应的研究

提出了在Ｎａ２ＨＰＯ４－ＮａＯＨ介质中,利用Ｃｕ（Ⅱ）－ＣＡＳ－ｅｎ－ＣＴＭＡＢ四元体系测定铜的新方法．试验表明,铜、铬天青Ｓ）（ＣＡＳ）、乙二胺（ｅｎ）、溴化十六烷基三甲铵（ＣＴＭＡＢ）可迅速反应,生成黄绿色配合物．配合物的最大吸收峰位于５６０ ｎｍ处,表观摩尔吸光系数∈＝３．１６ Ｘ １０４Ｌ·ｍｏｌ－１·ｃｍ－１．铜量在０－１７ｐｇ／２５ ｍＬ范围内符合比耳定律本法适用于铝合金、粮食、人发及水中痕量铅的测定．