热处理对锻态2.5vol.%(TiB TiC)/Ti复合材料组织与性能的影响

研究了热处理条件对锻态2.5vol.%(TiB TiC)/Ti复合材料显微组织和力学性能的影响。结果表明：固溶时效处理对复合材料的基体组织特征有显著影响,在两相区进行固溶时效处理后,得到等轴和双态组织,随固溶温度的升高,初生α相含量逐渐降低,而β转变组织含量逐渐升高,当固溶温度超过β转变温度时,得到全片层组织。TiB和TiC增强相在热处理过程中较为稳定,形态与分布无明显变化。固溶时效处理后,锻态复合材料的拉伸强度提高而塑性降低,随固溶温度的升高,复合材料的室温拉伸强度和塑性均有明显增加,而650 oC下拉伸强度与塑性与室温下表现出相反的规律。复合材料经1050oC/2h/AC 600oC/6h/AC处理后综合性能最好,室温拉伸强度为1215.8MPa,延伸率为3.14%,650 oC下拉伸强度为629.9MPa,延伸率为15.9%。     

热处理工艺对超高碳钢显微组织及磨损性能的影响

研究了不同热处理条件下超高碳钢的微观组织,分析了滑动速度和载荷对其摩擦磨损性能的影响.结果表明,球化退火后,其组织由铸态时的细片状珠光体加网状碳化物变成球状或粒状的珠光体;正火后,高碳钢组织转变为片状珠光体加颗粒状碳化物;淬火+低温回火后,碳钢组织转变成回火马氏体.在球化退火、正火及淬火条件下,材料的摩擦系数均随滑动速度和载荷的增大而减小;磨损率则随载荷的增大而增大,随滑动速度的增大而减小.在相同条件下,高碳钢在淬火+低温回火处理后的摩擦系数和磨损率明显低于球化退火后的摩擦系数和磨损率.     

热处理对金属陶瓷组织和韧性的影响

研究了热处理对金属陶瓷冲击韧性和断裂韧性的影响。结果表明，固溶处理能够提高金属陶瓷的冲击韧性和断裂韧性，其中１１５０℃固溶处理效果最好。固溶强化效应的增加、位错密度的提高及硬质相邻接度的减少被认为是固溶处理改善韧性的主要原因。固溶处理后再进行时效处理能进一步提高金属陶瓷的韧性，因为时效消除了金属陶瓷试样的内应力及粘结相中析出了强化相γ′。     

热处理对Zn-11%Al-8%Cu-Mg合金组织性能的影响

研究了热处理对Zn-11%Al-8%Cu-Mg合金组织性能的影响。结果表明,热处理后锌合金晶粒细化,组织分布更加均匀,共晶组织的形貌变得圆整;热处理后的抗拉强度和伸长率增加,但布氏硬度有所下降,综合性能得到改善。     

Effect of Heat Treatment on the Microstructure and Mechanical Properties of the Modified 718 Alloy

M718 alloy with an extra high Mo content of 7.50 wt% which reduced Nb addition and increased Al and Ti additions within the composition specifications of 718 alloy has been designed to increase the service temperature of 718 alloy. And the effect of the heat treatment on the microstructure and mechanical properties of M718 alloy has been investigated in this study. The results showed that Laves phase precipitated on the grain boundaries of M718 alloy instead of d-Ni_3 Nb phase in718 alloy, and y'and y'phases precipitated in the matrix of M718 alloy as that in 718 alloy. Increasing the solution temperature from 960 to 1050 ℃ noticeably reduced the intergranular precipitation of Laves phase. The precipitation of Laves phase was appropriate at 1020 ℃ for improving the grain boundary cohesion. Increasing the two-stage aging temperatures markedly increased the sizes of y' andy'phases. As a result, the strength of M718 alloy increased.     

Microstructural Characterization of Pure Titanium Treated by Laser Surface Treatment Under Different Processing Parameters

Advanced characterization techniques are utilized to investigate the effect of laser surface treatment on microstructural evolution of pure titanium(Ti). The results show that there are three distinctly different types of microstructure from surface to substrate in Ti samples, including phase transformation and solidification microstructure in zone I(melting zone); insufficient recrystallization grains with residual a martensitic plates in zone II(heat-affected zone, HAZ); fully recrystallization microstructure in zone III(base metal, BM). The hardness evolution profiles under different laser treatment parameters are similar.The highest hardness in MZ is ascribed to a plate, while the lowest hardness value in HAZ is due to the insufficiently recrystallized grains. The metallurgical process on the laser-modified Ti samples is systematically discussed in this work.     

热处理对Mg-Zn-Y合金显微组织和显微硬度的影响

本文采用铜模铸造方法制备出的Mg-Zn-Y合金,对所制试样进行两种不同工艺的热处理,并研究热处理对该合金的微观组织和显微硬度的影响。研究发现T6（420℃×24h＋150℃）态和高温退火（550℃×2h）态的合金晶粒中分散着一些小的颗粒相,T6态的絮状组织发生分离、显微硬度降低,而高温退火态合金的显微硬度却有一定程度的升高。     

半固态等温处理对Cu-Ca合金组织的影响

通过对比Cu-Ca合金铸态组织,研究了半固态等温处理主要工艺参数对半固态Cu-Ca合金组织的影响,得出了其半固态组织的演变规律。结果表明,在半固态等温处理工艺参数中,影响组织的主要参数为等温温度和保温时间。在一定选择范围内,随着等温温度的升高和保温时间的延长,组织将发生由树枝晶组织到非枝晶组织的一系列转变。研究发现,保温温度为957～967℃,等温时间为45～60min时,合金的球化效果最好,圆整度最高。     

钛合金焊缝组织循环热处理及球化过程分析

针对钛合金焊缝组织不均匀、脆性大、塑性差等问题,提出一种针对焊接接头的新型热处理工艺:α+β与α两相区循环热处理,讨论了不同热处理工艺对组织形貌的影响,得到由具有一定比例的等轴α相、条状α相及β转变相组织,提高循环次数球化的α相增多,长径比明显减小,有明显的球状的α相,其长径比普遍小于3,除此之外在球化的α相周围分布着取向各有不同的细小条状α相。经过4次循环热处理的焊接接头拉伸得到强塑积达到14441.17MPa·%,焊接接头的塑性有所提高。结合EBSD、TEM等测试结果的分析,解释了该现象产生的原因,解释针状α相的断裂及条状α相的长大,在热处理过程中位错、孪晶的移动形成的亚晶界及β相的分解促进了热蚀坑的形成过程。该方法可以有效地将焊接组织均匀化,缓解焊接组织的应力集中,在未来航空航天领域有很重要的应用价值。     

热处理对新型Al-Mg-Si合金微观组织及性能的影响

对4种通过热力学计算优化选出的Al-Mg-Si合金进行了电磁搅拌及热处理试验研究。通过微观组织和性能的分析比较发现,电磁搅拌能显著改善合金的显微组织结构,为后续的热处理提供有利的显微组织条件,进而增强合金的时效强化效果,改善合金的塑性。同时发现,Mg、Si含量对合金的显微组织和性能具有不同的影响,这与合金不同的平衡凝固过程有关。该试验研究为进一步优化适合半固态成形的低成本高性能铝合金提供了依据。     

热处理对新型Al-Mg-Si合金微观组织及性能的影响

对4种通过热力学计算优化选出的Al-Mg-Si合金进行了电磁搅拌及热处理试验研究。通过微观组织和性能的分析比较发现，电磁搅拌能显著改善合金的显微组织结构，为后续的热处理提供有利的显微组织条件，进而增强合金的时效强化效果，改善合金的塑性。同时发现，Mg、Si含量对合金的显微组织和性能具有不同的影响。这与合金不同的平衡凝固过程有关。该试验研究为进一步优化适合半固态成形的低成本高性能铝合金提供了依据。     

Effects of Ti and Cu on the Microstructure Evolution of AlCoCrFeNi High-Entropy Alloy During Heat Treatment

The microstructure evolution of AlCoCrFeNiTi_(0.5) alloy and AlCoCrFeNiCu alloy during heat treatment was systematically studied,to reveal the influence rules of chemical activity of adding element on the microstructure evolution of AlCoCrFeNi system.Owing to the negative mixing enthalpy with the constituent elements,Ti element was mainly dissolved in the Al-Nirich phases,and aggravated the lattice distortion of B2 phase.The structure variation of BCC phase by adding Ti inhibited the formation of FCC phase and enhanced the precipitation of σ phase during heat treatment.Owing to the positive mixing enthalpy with constituent elements,Cu element tended to be repelled to the ID region and formed metastable Cu-rich FCC1 phase which would transform into Cu-Al-Ni-rich FCC2 phase with increasing temperature.The addition of Cu inhibited the precipitation of σ phase during heat treatment.Adding Ti maintained the stable dendritic morphology,while adding Cu reduced the thermal stability of microstructure.Two dramatic morphology changes occurred at 1000~℃ and 1100~℃ in the AlCoCrFeNiCu alloy.The lattice distortion of phase in AlCoCrFeNiTi_(0.5) alloy was aggravated with increasing temperature up to 800~℃,then relaxed together with the dissolution of σ phase when temperature was above 900~℃.The variation in lattice distortion dominated the hardness of AlCoCrFeNiTi_(0.5) alloy.With increasing heating temperature,the increasing volume fraction of region with FCC structure due to the transformation between FCC phases,and the pronounced coarsening in microstructure due to the reduced thermal stability,resulted in the mainly decreasing trend in the hardness of AlCoCrFeNiCu alloy.     

SiC含量对近β钛合金显微组织及力学性能的影响

通过真空非自耗熔炼工艺制备了不同SiCp添加量(0wt.%、0.1wt.%、0.4wt.%、1.wt.%)的近β钛合金。采用X射线衍射仪(XRD)、扫描电镜(SEM)、维氏显微硬度计和万能材料试验机,系统研究了SiCp添加量对近β钛合金显微组织及力学性能的影响规律。研究结果表明,不同SiCp添加量的近β钛合金主要由α-Ti、β-Ti和TiC所组成。近β钛合金的初生β晶粒尺寸取决于SiCp的添加量,SiCp添加量由0%增加到1wt.%时,近β钛合金初生β晶粒尺寸由639μm降低至323μm。由于受细晶强化、TiC承载强化以及Si的固溶强化的影响,随着SiCp添加量的增加,近β钛合金的显微硬度、压缩强度有显著提高,而压缩率却明显降低。     

均匀化热处理对牙科烤瓷无钯高金合金组织性能的影响

研究了均匀化热处理对一种无钯牙科高金烤瓷合金组织性能的影响,对其进行了950℃保温30min的均匀化处理,然后快速在冰水混合物中淬火,并对之做了一系列测试分析.实验结果显示合金在均匀化热处理后,组织显著均匀化,硬度显著降低.淬火后的合金仍为α1和α2两相组织,但富铂的α2相颗粒的量比铸态组织明显减少,颗粒的尺寸也有所减小,SEM下观察有很强的立体感.作者认为合金高温淬火后仍为两相组织,而非单一均匀相,主要与热处理温度和材料的固态相变温度相距较近有关.     

Effect of Solution Treatment on the Microstructure and Mechanical Properties of Sand-Cast Mg–9Gd–4Y–0.5Zr Alloy

Sand-cast Mg–9Gd–4Y–0.5 Zr(wt%) alloy was solution-treated at 500–565 ℃ in the time range of 0.5–30 h in air or vacuum to investigate its microstructure evolution and mechanical properties. The results showed that solution treatment temperature had a significant influence on the dissolving rate of eutectic phase and grain growth. Taken both of them into consideration, 510–520 ℃ was considered to be the optimum solution treatment temperature range for this alloy.It should be noted that the trace(0.4–0.9 vol%) and insoluble cuboid-shaped phase precipitated during solution treatment was identified to be YH2, of which the hydrogen was thought to come from both the melting and solution heating process.In addition, the 3D morphology and dissolving process of Mg24(Gd,Y)5 eutectic phases in the as-cast alloy were also discussed via in-situ observation under X-ray tomography.     

热处理对超(超)临界材料组织性能的影响

选用2Cr11Mo1VNbN、10Cr9W2MoVNbNB、1Cr11Co3W3NiMoVNbNB 3种超(超)临界机组耐热材料,进行热处理工艺、力学性能、金相组织研究.通过实验确定了3种材料最合适的热处理工艺参数:2Cr11Mo1VNbN、10Cr9W2MoVNbNB钢的最佳淬火、回火温度分别为1 060～1 080℃、660～680℃;1Cr11Co3W3NiMoVNbNB钢的最佳淬火、回火温度分别为1080～1 100℃、680～700℃;观察分析发现,3种钢在1 080℃淬火、680℃左右回火的组织均为回火马氏体;找出了材料热处理后的强度与冲击韧度之间的关系.     

热处理对耐磨合金铸铁组织和性能的影响

研究了奥氏体化温度及时间、回火温度及时间等热处理工艺参数对耐磨合金铸铁组织和性能的影响。结果表明,880℃保温40 min后油淬,200℃保温50 min回火后,合金的组织为回火马氏体、莱氏体和一些块状碳化物,洛氏硬度大于53 HRC,且冲击韧度和耐磨性能良好。     

等温退火对ZTC18钛合金组织与性能的影响

研究了等温退火温度对ZTC18钛合金组织和性能的影响。结果表明：ZTC18钛合金在热等静压＋等温退火条件下,随着等温退火温度的升高,初生α相由不规则针状和棒状逐渐转变为平直棒状;次生α相由细小弥散分布到呈平行排列,并最终粗化长大呈棒状和颗粒状。拉伸试验结果表明,试样强度随等温退火温度升高逐渐降低,而塑性逐渐增加。合金强度和塑性主要受初生α相的形态以及次生α相的形态和数量控制。     

高温形变热处理对Ti-1300合金组织及硬度的影响

采用光学显微镜、扫描电子显微镜、Gleeble-3800热模拟试验机以及IMVS-1000JMT2数显维氏显微硬度仪研究了等温变形条件下形变热处理对Ti-1300合金组织及硬度性能的影响。结果表明:高温形变热处理可以明显的细化Ti-1300合金的显微组织,并在一定程度上提高合金的力学性能。热轧态合金的组织中粗大块状和长条状α相经高温压缩变形后具有明显的等轴均匀化趋势,然后分别经过淬火时效和固溶时效处理后合金的组织主要由板条状初生α相,针状次生α相以及β相组成,初生α相和次生α相主要分布于晶界和β基体上。与淬火时效态相比,固溶时效态合金的硬度随初生α相板条厚度和含量的增加而降低,最后对影响的机理进行探讨和分析。