固溶时效对上引拉铸Cu-0.3Cr-0.1Zr组织性能的影响

用扫描电镜(SEM)、透射电子显微镜(TEM)、涡流电导率测量仪和万能试验机测试分别测量了上引拉铸拉拔之后固溶时效对Cu-0.3Cr-0.1Zr合金抗拉强度及导电率性能的影响,用金相显微镜观察不同拉拔加工率下固溶的显微组织.并探讨了合金的强化机理.结果表明:上引Cu-0.3Cr-0.1Zr合金铸锭经过75％冷拉变形后固溶其组织和力学性能较好.经时效后的固溶态Cu-0.3Cr-0.1Zr合金,抗拉强度和导电率迅速上升,随着时间时间的延长,其抗拉强度达到峰值后呈下降趋势,而导电率则继续上升.Cu-Cr-Zr合金析出强化的重要因素是大量共格弥散的析出相,以共格强化机制估算的强化值423MPa与实验结果415MPa相近.     

热处理工艺对高强度含铜9Ni钢组织和性能的影晌

随着液化天然气（LNG）储罐朝着大型化发展,在不增加容器壁厚的情况下,必须提高钢板强度。在传统9Ni钢中添加Cu,通过析出强化,使其强度水平得到显著提高。提出一种新型含1．25％Cu（质量分数）9Ni钢。试验钢经过控轧直接淬火（DQ）;研究了DO材料分别经过1）QLT（奥氏体（γ）单相区淬火（Q）＋两相区（α＋γ）淬火...     

Interfacial Microstructure and Mechanical Strength of 93W/Ta Diffusion-Bonded Joints with Ni Interlayer

93W alloy and Ta metal were successfully diffusion bonded using a Ni interlayer. Ni₄W was found at the W-Ni interface, and Ni₃Ta and Ni₂Ta were formed at the Ni-Ta interface. The shear strength of the joints increases with increasing holding time, reaching a value of 202 MPa for a joint prepared using a 90-minute holding time at 1103 K (830 °C) and 20 MPa. The fracture of this joint occurred within the Ni/Ta interface.     

Effect of Temperature on the Die Shear Strength of a Au-Sn SLID Bond

The effect of temperature on the die shear strength of a optimized Au-Sn solid–liquid interdiffusion SLID bond, a reliable high temperature die attach and interconnect technology, was investigated. The shear strength was greatly reduced with temperature from 140 MPa at room temperature to 20 MPa at 573 K (300 °C). This reduction was unexpected since the melting point of a Au-Sn SLID bond is 795 K (522 °C). Fractographic studies revealed a change in fracture mode with increasing temperatures. This work emphasizes the importance of performing bond strength quantification at the intended application temperature.     

Zn及Ni元素对喷射成形铝合金组织特征和时效行为的影响

Microstructure and aging behavior of spayformed Al-Zn-Mg-Cu alloys were investigated as a func.tion of alloying element addition. It reveals that the grains of the as-deposited alloys are refined with increasing Zn element, while the function of the Ni addition is to reduce grain boundary particles and eutectic in the as-extruded condition. Particles containing Mg and Zn are found to be increased with Zn content increasing, while the role of Ni is to reduce both number and size of these particles. During artificial aging, the increment of Zn content produces not much effect on peak hardness, in addition to an accelerated overage softening. An addition of about 0.13% Ni,however, gives rise to not only an improved peak hardness but also an improvement of property stability at the aging temperature.     

热处理温度对高强变形铝青铜的组织和力学性能的影响

针对一种新型高强变形铝青铜合金,考察了淬火温度和回火温度对该合金的微观组织和力学性能的影响。研究结果表明,淬火温度越高,合金内部的β'马氏体相越多,材料的硬度越高,但淬火温度过高时,由于针片状α相的出现,使材料的强度和塑性有较大下降。试验合金适宜的淬火温度为900℃。淬火态材料经低温回火,强度可进一步提高,400℃回火时材料的强度和硬度达到峰值,此后随着回火温度的升高,材料的强度和硬度逐渐下降,延伸率逐渐提高。600℃回火态材料的抗拉强度和延伸率分别达到900 MPa和17%以上,具有优良的强韧配合。     

铌含量对17%Cr超纯铁素体不锈钢组织与高温强度的影响

随着汽车行业的发展,汽车排气系统热端用铁素体不锈钢的使用温度越来越高,高温性能成为限制其发展的关键性能。研究铌含量对铁素体不锈钢组织与高温性能的影响可以指导钢种设计和工业化生产。选取了2种17%Cr超纯铁素体不锈钢进行高温时效试验,结果表明:铌的质量分数为0.2%时,铌没有明显的强化作用,950℃高温下晶粒迅速长大,高温强度迅速降低;铌的质量分数为0.4%时,在950℃高温下时效,材料中析出弥散第二相粒子Fe2Nb,阻止晶粒长大,提高强度,防止高温引起的材料软化。材料的高温强度是由固溶铌以及铌析出物的共同作用引起的,当固溶铌析出形成析出物时,固溶铌含量减少引起的强度降低以及析出引起强度升高的竞争导致了材料的强度变化。     

时效温度对不同铜含量超低碳钢铜析出的影响

对两种不同铜含量的超低碳钢在400～600℃温度区间等温时效1h,通过扫描电镜和透射电镜观察分析时效温度对铜析出的影响。结果表明:随着时效处理温度升高,两种含铜试验钢铜析出物数量均呈先增加后减少的趋势;含铜量高的钢(2.04%Cu)在500℃时效处理后析出物数量达到峰值,含铜量低的钢(1.04%Cu)达到值的时效处理温度为550℃;在相同温度时效处理后,含铜量高的(2.04%Cu)钢的析出物量比含铜量低的钢(1.04%Cu)多,但在600℃时效处理时,两者的差别变小。     

Time Effect on Shear Strength and Permeability of Fly Ash

This paper investigates the effect of time on the shear strength and the permeability of fly ash, a major solid by-product of thermoelectric power plants. Direct shear tests using Mikasa's apparatus, conventional permeability tests, and consolidation tests were conducted on two silt-size fly ashes, with low free lime contents, obtained from two different power plants. The results show that the immediate settling of both fly ashes takes place in a short period of time during consolidation and does not change with time. The rate of increase in shear strength with time is different depending on the pozzolanic reactions taking place for the two ashes. The permeability tests under constant stresses of 49 and 98 kPa for 12 days show that the coefficient of permeability for the tested ashes is between 10?6 and 10?7 m∕s. During this period the coefficient of permeability either remains constant (for the case of the ash with a lower free lime content) or is slightly reduced (for the ash with a higher free lime content). The practical implications and the limitations of using low lime silt-size fly ash in vertical drains in the stabilization of soft ground are also discussed.     

烧结温度对掺Nd3+的Ni-Zn铁氧体组织和磁性能的影响

研究了不同温度烧结对掺Nd3+的Ni-Zn铁氧体组织和磁性能的影响。随着烧结温度的增加,含Nd3+铁氧体粒度和数量相应增加,气孔明显减少。实验发现,烧结温度为1250℃时的试样有较好的综合性能,不仅具有较高的磁导率而且损耗也较小。     

时效对超高强含钪铝合金组织和性能的影响

采用维氏硬度测量、室温拉伸性能测试和显微组织结构分析,研究了不同时效制度下Al-Zn-Cu-Mg-Sc-Zr合金的力学性能、腐蚀性能和显微组织。结果表明,合金具有显著的时效硬化效应,随时效温度的升高,合金达到时效硬度峰值的时间缩短。合金适宜的时效制度为120℃/24 h。此时,合金的抗拉强度、屈服强度、伸长率和维氏硬度分别为696 MPa、654 MPa、11.1%和211.2 HV。合金中主要强化相为GP区和η′相,主要强化作用为沉淀强化及弥散强化。时效过程中Al3Sc和Al3(Sc,Zr)质点表现出较强的热稳定性;合金抗晶间腐蚀能力随时效时间的延长而增强。     

Effect of Aging Treatment on the Microstructure and Resistivity of a Nickel-Base Superalloy

The γ′ precipitation behavior of age-hardened WASPALOY, aged at 998 K, 1073 K, and 1148 K (725 °C, 800 °C, and 875 °C) for times ranging from 0.5 to 263.5 hours, were evaluated via analysis of ultra small angle X-ray scattering (USAXS) curves and scanning electron microscopy (SEM) micrographs. The USAXS spectra revealed a single precipitate size distribution at the earliest aging times, which evolves into a bimodal precipitate size distribution at later aging times. The primary precipitate radius displayed t ^1/3 coarsening dependence for aging at 1073 K and 1148 K (800 °C and 875 °C); however, the primary radius increased with t ^0.4 dependence at 998 K (725 °C), most likely due to mixed growth and coarsening. A figure of merit, η′, consisting of two terms, one associated with precipitate size and volume fraction and the other with compositional fluctuations, was proposed. η′ shows direct empirical correlations with changes in the measured electrical resistivity.     

Comparison of Room Temperature and Cryo-Deformation Effects on Mechanical Properties and Microstructure of Copper

The objective of this work is to study the effect of room temperature (RT) and liquid nitrogen temperature (LNT) rolling on mechanical properties of the pure copper. For the same percentage deformation, LNT samples show a significant increase in tensile strength and hardness value compared to RT samples. Microstructural investigation shows a large misorientation change between RT and LNT samples when we use grain orientation spread (GOS) as a measure of microstructural change. The mechanical property and microstructural changes are correlated with calorimetry experiments. We also present some preliminary results from our work on wire drawing at RT and LNT.     

Microstructure and Microtexture Evolution of Shear Localization in Dynamic Deformation with Different Strains in Annealed Copper

Shear localizations with different strains in annealed copper were obtained by a modified split Hopkinson pressure bar. Microstructure and microtexture evolution of the shear localization regions were examined using optical microscopy, electron backscatter diffraction technique, and transmission electron microscopy. The results show that both the mechanical response and deformation behavior are correlated closely to the shear strains. The elongated dislocation cells, stretched subgrains, and the refinement of subgrains are observed within shear localizations during dynamic deformation. Ultrafine grains of 100 to 300 nm with high-angle-boundaries are produced within the shear band with the shear strain of 5.8. Microtexture characterization reveals that a stable orientation, in which 〈110〉 directions of the crystals tend to align with the shear direction, develops both in the deformation and recrystallization areas. The {111} planes of the crystals tend to parallel to the shear plane in the deformation area, whereas the aggregated extent of this orientation becomes weak in the recrystallization area. In addition, some grains exist with the {100} planes parallel to the shear plane in the deformation and recrystallization areas. The rotational dynamic recrystallization is a reasonable mechanism for the microstructure evolution. The effects of cooling stage on the growth of grains and the change of dislocation density are estimated as a complementarity to this mechanism.     

双级时效制度对7150铝合金微观组织和性能的影响

采用拉伸测试、电导率测试和透射电镜等手段研究了双级时效制度对7150铝合金的力学性能、电导率和微观组织的影响。结果表明:在本研究范围内,第一级时效制度对合金的力学性能和电导率影响不大;合金经过120℃/8h+160℃/6h,可以达到与单级峰时效处理相当的抗拉强度,并且电导率有明显提高;第二级时效温度为168℃时效时,相比在160℃进行第二级时效,合金在具有同等电导率水平时,损失的强度相对较多,但时效时间明显变短;120℃/8h+160℃/32h双级时效后,合金的抗拉强度为560MPa,屈服强度为520MPa,延伸率为11.5%,电导率22.7MS.m-1,晶内沉淀析出相以η′和η为主,晶界析出相完全断开。     

微观组织对C-Mn钢低温脆性的影响

常规TMCP工艺生产的C-Mn钢厚板出现-40℃低温冲击脆化现象,为了确定引起脆化的微观组织因素,通过实验室重复冲击实验、微观组织的定量化统计分析、断口观察发现钢板不同部位的铁素体晶粒尺寸分布和珠光体含量有极大差别,解理脆性断裂试样铁素体晶粒粗大且服从对数正态分布,珠光体含量高于20%,而韧性断裂试样具有细小均匀的铁素体晶粒,晶粒尺寸服从正态分布,珠光体分布均匀、含量低于10%。经验公式计算表明脆性断裂试样的铁素体晶粒尺寸和珠光体含量使韧脆转变温度比韧性断裂试样高约60℃,因此可以确定铁素体晶粒尺寸和珠光体含量是影响钢的低温脆性的主要因素。靠近钢板表面部位具有与脆性断裂试样类似的微观组织特征,而靠近厚度中间部位具有与韧性断裂类似的微观组织特征,这使得表面与厚度中间部位韧脆转变温度近60℃的差异。厚度方向微观组织差异是由钢板轧后的不同厚度发生相变的过冷度差异引起的,而低温终轧是导致钢板表面温度低而在空冷阶段先发生相变的工艺因素。     

时效温度对S32101双相不锈钢组织和力学性能的影响

利用光学显微镜、铁素体仪进行了硬度和拉伸实验,研究了S32101双相不锈钢不同时效态下组织与力学性能之间的关系。研究结果表明,随着时效温度的升高,S32101双相不锈钢的屈服强度、抗拉强度和硬度减小,延伸率增大;析出相的产生是造成力学性能变化的主要原因,700℃为最敏感析出温度,900℃时析出相开始逐渐消失。     

时效温度对马氏体沉淀硬化不锈钢0Cr15Ni5WMoVNb力学性能的影响

0Cr15Ni5WMoVNb钢(%:0.068C、14.54Cr、5.32Ni、0.88W、0.92Mo、0.20V、0.10Nb)经5 t中频感应炉+2 t真空电渣重熔炉冶炼,经锻造、热轧成Φ45 mm棒材,试样经1 000℃30 min固溶空冷+-70℃2 h冷处理后进行400～600℃4 h时效空冷。试验结果表明,在450℃时效0Cr15Ni5WMoVNb钢的强度最大,以准解理断裂为主,冲击功低为40 J,随时效温度上升,冲击功显著上升,强度下降,在510℃时效该钢有良好的强韧性,抗拉强度R_m 1300 MPa,屈服强度R_(p0.2)1100 MPa,冲击能A_(KV) 100 J。     

钇对铜和铜硅合金组织与性能的影响

用扫描电镜、能谱仪、Ｘ射线衍射、硬度测量等方法，研究了铜钇和铜硅钇合金的组织与性能。实验表明，钇的加入对铜和铜硅合金的组织有明显的变质作用，并提高了合金的硬度。     

固溶时效工艺对Cu-Ni-Si合金组织和性能的影响

用扫描电镜(SEM)、硬度计、涡流电导率测量仪和万能试验机测试分别测量了在850 ～950℃固溶温度及400 ～ 500℃时效不同时间下对Cu-1.5 Ni-0.6Si合金硬度及电导率性能的影响,用金相显微镜观察不同固溶温度下合金的组织.并对合金拉伸形貌断口进行了分析.探讨了合金的强化机理.结果表明:时效前随着固溶温度的升高,材料的硬度及电导率均随之下降,但电导率下降的幅度很小.随着固溶温度的增加,其再结晶程度越来越高,到900℃时组织已是完全再结晶组织,温度继续升高,晶粒会发生长大.时效析出为Cu-1.5 Ni-0.6Si合金的主要强化手段.Cu-1.5Ni-0.6Si固溶后经不同温度时效后,时效初期硬度和电导率快速上升.随后硬度到达峰值后缓慢下降,而电导率继续上升.经过900℃×1h水淬+450℃×2h空冷处理后,合金得到良好的综合性能;其抗拉强度为780.7 MPa,伸长率为15.1％,电导率为40.2％ IACS.