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.     

倒双级时效对镍基高温合金组织及高温拉伸性能的影响

 研究了固溶+两段时效热处理工艺对镍基高温合金组织及性能的影响。结果表明：镍基高温合金中的γ′相粒子半径大于40 nm时，位错与γ′相的交互作用由切割机制转变为绕过机制，合金强度明显降低；γ′相的长大规律符合Oswald熟化过程规律；合金在第二段时效过程中，晶界碳化物转变成颗粒状，使其塑性显著提高。     

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。     

加热温度对微合金高强钢奥氏体组织及其再结晶的影响

 通过实验室模拟实际生产中的加热过程及单道次压缩热模拟试验,结合组织观察分析方法,回火硬度法研究了一种Nb V Ti微合金高强管线钢加热温度与奥氏体组织,合金元素溶解及析出的关系,并对不同温度加热后奥氏体的动态再结晶行为及其组织进行了研究。试验结果表明,随加热温度的升高,奥氏体晶粒尺寸逐渐增大,在1 200 ℃以上易出现粗大晶粒,加热温度过高形成的粗大奥氏体晶粒延缓了再结晶行为,容易造成混晶现象。     

回火温度对20SiMnMo高强度钢微观组织与力学性能的影响

采用光学显微镜、扫描电子显微镜、洛氏硬度计、万能力学试验机以及冲击试验机研究了950℃淬火220℃、240℃、260℃、280℃、300℃和320℃3 h回火试验对20SiMnMo高强度钢（/%:0.22C,0.80Si,1.00Mn,0.40Mo,0.72Cr,0.20Ni）微观组织和力学性能的影响。结果表明,随着回火温度的升高,试验钢的硬度、强度不断下降,伸长率、室温冲击功先升高再降低。当260℃回火时,试验钢具有均匀细长的板条马氏体组织,其强塑韧综合力学性能最佳:硬度值44.8HRC、AKV2冲击功75.3 J、抗拉强度1 278 MPa、屈服强度1 210 MPa、伸长率15.5%。     

长期时效对DD407单晶高温合金组织和中温性能的影响

研究了DD407单晶高温合金在900℃长期无应力时效过程中,组织的演变规律及其对中温性能的影响。研究结果表明：经长达3 000 h的时效后,合金的组织稳定,无有害相析出,7 6 0℃中温强度稳定,但伸长率显著提高。     

Effect of Tempering Temperature on Microstructure and Mechanical Properties of Steel Containing Ni of 9 %

  Mechanical properties of quenching, intercritical quenching and tempering (QLT) treated steel containing Ni of 9% were evaluated from specimens subject to various tempering temperatures. The detailed microstructures of steel containing Ni of 9% at different tempering temperatures were observed by optical microscope (OM) and transmission electron microscope (TEM). The volume fraction of austenite was estimated by XRD. The results show that high strength and cryogenic toughness of steel containing Ni of 9% are obtained when the tempering temperature are between 540 and 580 ℃. The microstructure keeps the dual phase lamellar structure after the intercritical quenching and there is cementite created in the Ni rich constituents when tempering temperature is 540 ℃. When tempering temperatures are between 560 and 580 ℃, the reversed austenites (γ′) grow up and the dual phase lamellar structure is not clear. The γ′ becomes instable at 600 ℃. When tempered at temperature ranging from 500 to 520 ℃, the increase of dislocation density in the lamellar matrix makes both tensile strength and yield strength decrease. When tempered at 540 ℃ and higher temperature, the yield strength decreases continuously because the C and alloying elements in the matrix are absorbed by the cementite and the γ′, so the yield ratio is decreased by the γ′. There are two toughness mechanisms at different tempering temperatures. One is that the precipitation of cementite absorbs the carbon in the steel which plays a major role in improving cryogenic toughness at lower temperature. Another is that the γ′ and the purified matrix become major role at higher tempering temperature. When the tempering temperature is 600 ℃, the stability of γ′ is decreased quickly, even the transformation takes place at room temperature, which results in a sharp decrease of Charpy V impact energy at 77 K. The tempering temperature range is enlarged by the special distribution of cementite and the lamellar structure.     

时效温度对K487合金组织和性能的影响

 研究了不同时效温度对K487合金组织和性能的影响。结果表明,随时效温度提高,合金组织中γ′相尺寸增大,针状μ相减少,不规则块状和条状μ相边缘尖角变圆钝,合金强度下降,塑性提高。经900 ℃×5 h时效后,合金可获得较好的综合性能,其屈服强度约685 MPa,伸长率和断面收缩率分别达到105%和155%。     

温度参数对铌微合金高强度结构钢组织性能的影响

通过控轧控冷试验,力学性能检验和组织的光学显微观察,研究了温度参数对铌微合金钢组织性能的影响。结果表明:两阶段控轧及控冷所获晶粒尺寸明显小于常规轧制+快速冷却的晶粒尺寸;随冷却速率的增大或终冷温度的降低或精轧开轧温度的降低,试验钢晶粒细化,混晶程度加重,强度增大,塑性降低;精轧低温开轧利于韧性提高;铁素体混晶可能源于因铸坯中Nb(C,N)的不均匀分布造成的原始奥氏体混晶,粗轧大压缩比轧制可以消除这种混晶现象。     

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。     

预处理温度对00Cr12Ni10MoTi马氏体不锈钢强度的影响

 研究了预处理温度对00Cr12Ni10MoTi马氏体不锈钢强度的影响。研究结果表明：在较低预处理温度下,通过非扩散α′→γ逆转变形成的奥氏体遗传了原始的锻态组织。而在950℃以上温度预处理则形成再结晶的奥氏体。由于最终750℃固溶处理遗传了预处理组织,因此预处理对钢的强度有明显的影响。材料在低于850℃预处理时最终组织中残余奥氏体量较高,不利于提高强度。850℃预处理出现峰值强度,继续提高预处理温度,强度又下降。由于950℃以上预处理形成再结晶的奥氏体,使得最终热处理后的强度稳定在较低的水平。     

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.     

回火温度对渗碳钢18Cr2Ni4WA组织和硬度的影响

为满足用户加工HBW硬度值≤269的需要,降低18Cr2Ni4WA钢Φ60 mm材硬度,利用连轧厂实际辊底式退火炉进行了630～750℃5h炉冷至500℃空冷的回火试验,并借助金相显微镜对18Cr2Ni4WA钢不同回火温度下的组织进行了分析,以确定最佳的回火温度。结果表明,18Cr2Ni4WA钢随回火温度的升高硬度先下降后上升,当温度为670℃时,钢材平均HBW硬度值最低(HBW238左右),回火组织为均匀的回火珠光体组织。