铸造铝合金缺陷分析与热处理工艺研究

本文论述了铸造铝合金易产生的质量缺陷和预防措施;阐述了固溶淬火温度、保温时间、时效工艺等对铸造铝合金组织和性能的影响;推荐了合理的热处理工艺参数.     

时效工艺对Al-11Zn-2.4Mg-1.1Cu-0.15Zr铝合金性能的影响

Al-11Zn-2.4Mg-1.1Cu-0.15Zr铝合金自然时效的速度慢,且不稳定,故一般不在自然时效状态下应用.为了获得更高的强度、较好的抗蚀性、较低的疲劳裂纹扩展速度以及性能的稳定,该系合金一般采用人工时效处理.热处理工艺参数主要包括固溶处理温度、固溶处理时间、时效温度、时效时间.本实验研究了时效工艺对Al-11Zn-2.4Mg-1.1Cu-0.15Zr铝合金性能的影响,旨在摸索Al-11Zn-2.4Mg-1.1Cu-0.15Zr铝合金的合理热处理工艺.     

基于响应面法对211ZX新型高强铝合金固溶工艺的优化设计

采用响应面法研究了固溶工艺对211ZX高强铝合金强度和塑性的影响规律。以固溶温度和固溶时间为自变量,抗拉强度、伸长率和显微硬度为目标函数,建立了固溶工艺和力学性能间的多项式模型,通过绘制的三维曲面响应图获得了力学性能对固溶处理的响应关系,并找到固溶工艺为552.9℃×13.1 h, 500℃×16.3 h, 556.1℃×12.0 h时分别使抗拉强度、伸长率和维氏硬度达到最大值为469.8 MPa, 15.9%, HV 156.6。并通过Matlab遗传算法工具对建立的模型进行力学目标参量约束条件下的多目标优化,获得了Pareto优化解集,从中找到了复合使役条件、综合性能优异的五组固溶工艺参数。从优化求解出的5组最佳工艺中任意选取两组固溶工艺下的试样进行力学性能测试,发现模型计算的工艺参数能够较好的控制该合金的抗拉强度、伸长率和显微硬度,并且综合力学性能有了显著提高。结果同时表明,采用响应面法对该铝合金的工艺参数进行设计可获得理想的力学性能,该方法提供了一种新的热处理设计思路和热处理工艺优化方法。     

热处理工艺对6A02合金管材组织性能的影响

采用光学显微镜(OM)、扫描电子显微镜(SEM)、能谱仪(EDX)、正交试验及力学性能测试等手段研究了热处理工艺对6A02铝合金管材组织性能的影响。结果表明:6A02铝合金管材的挤压态组织分布着形貌各异、尺寸大小约为0.5~8.0μm的Al-Fe-Si-Mn-Cu相。固溶处理后,细小点状的Al-Fe-Si-Mn-Cu相基本回溶到基体中,粗大不规则的Al-Fe-Si-Mn-Cu相残留下来。该残留相尺寸在510℃固溶时略微变大,在520℃固溶时尺寸有所变小。正交试验极差分析表明,以抗拉强度和屈服强度为考核指标时,各影响因素的主次关系排序为:时效温度固溶时间固溶温度时效时间。方差分析表明,热处理过程中,时效温度对合金抗拉强度的影响显著,而时效温度、固溶时间及固溶温度对合金屈服强度的影响显著。6A02铝合金最佳的固溶-时效工艺为520℃×40 min+160℃×12 h,对应的力学性能指标分别达:抗拉强度σb=333.83 MPa,屈服强度σs=321.11 MPa和延伸率δ=17.28%。     

热处理工艺对6110A铝合金棒材性能和组织的影响

文章以汽车配件用6110A铝合金棒材为研究对象,通过室温静态单向拉伸检测、布氏硬度检测、金相组织观察及拉伸断口组织分析,借助正交试验分析,来研究热处理工艺对6110A合金的性能和组织的影响。结果表明,通过极差分析结果,对6110A铝合金屈服强度和硬度影响程度的主次关系依次为,时效温度、固溶时间、固溶温度、时效时间;对合金抗拉强度影响程度的主次关系依次为,时效温度、固溶温度、固溶时间、时效时间;因此在6110A铝合金的热处理工艺中必须合理的选择控制时效温度。     

双级时效对7075铝合金力学性能的影响

本文研究了7075铝合金固溶处理后双级时效热处理工艺,分析了双级时效工艺对7075铝合金力学性能的影响.合金成份一定的7075铝合金挤压型材,经470℃2h固溶后,再经120℃×6h+165℃x5h双级时效时能获得较好的综合性能,为7075铝合金时效热处理工艺参数的确定及优化提供参考依据.     

含Sc2024铝合金热处理工艺优化

介绍了2024合金的用途、传统热处理工艺制度及其相构成,通过对样品的固溶、时效优化处理找到最佳的含钪2024铝合金热处理工艺,最佳处理工艺为：固溶温度500℃、固溶时间为4小时、60℃水淬,预时效温度为130℃、时间为6小时,最终时效温度为190％、时间为18小时。     

双级时效对7020铝合金挤压板材组织与性能的影响

挤压态7020铝合金板材经过470℃固溶1h后进行正交实验。采用室温拉伸机、材料显微镜、体式显微镜研究双级时效对7020铝合金挤压板材组织及力学性能的影响。结果表明,经极差分析,材料屈服强度、抗拉强度影响因子重要性排序为:终时效温度初时效温度终时效时间初时效时间;材料伸长率影响因子重要性排序为:终时效温度初时效温度初时效时间终时效时间;正交实验综合力学性能最优双级时效工艺为120℃×8h+150℃×15h;合金经过120℃×8h+150℃×15h后,其断口裂纹扩展区较小,材料韧性较好,微观组织均匀且在其晶界处均匀弥散分布细小第二相。     

高强高导稀土铝合金导线的热处理工艺正交试验优化

采用正交试验设计方法对稀土铝合金导线的热处理工艺进行优化,并对稀土铝合金导线的力学性能和导电率进行了系统的分析检测。结果表明:对稀土铝合金导线强度和导电率影响最明显的因素是时效温度,其次是固溶温度和固溶时间,最不明显的因素是时效时间。稀土铝合金导线的最优热处理工艺为:530℃固溶1h,190℃时效12h。经最优热处理工艺热处理后,稀土铝合金导线可以获得最优的强度和导电率匹配关系,稀土铝合金导线具有高强度和高导电率,其抗拉强度为322.6MPa,屈服强度为266.5MPa,伸长率为6.44%,导电率为56.1%IACS。     

固溶时效工艺对GH4169高温合金组织和性能的影响

本文通过G H4169合金在不同热处理工艺条件下的固溶和时效处理实验,研究了固溶温度和时效温度对合金的微观组织和性能的影响.结果表明:720℃时效处理工艺下,1050℃以上固溶处理,晶粒明显细化,1100℃下晶粒最细,随着固溶处理温度的升高,时效析出的第二相含量增加;620℃时效处理工艺下,1050℃固溶时效析出相的含...     

Effect of heat treatment on microstructure and mechanical properties of plastic mold steel 10Ni2Cr2MnCuMoVAl

The effects of solution and aging treatment on microstructure and mechanical properties of 10Ni2Cr2MnCuMoVAl plastic mold steel were experimentally studied. The results show that the dominant microstructure of 10Ni2Cr2MnCuMoVAl steel after solid solution treatment is lath martensite, and higher solution temperature results to larger width of martensite, while the highest value of hardness could be obtained after solution treatment at 890??. After aging, the microstructure consists of lath martensite, granular bainite and carbides. For steel aged at 460-520??, the strength of the material gradually increased with higher aging temperature, while the toughness decreased gradually. When the temperature exceeded 520??, higher temperature led to decreased hardness and increased toughness. Compared the mechanical properties of steel aged at 540?? for different time, the test steel reached the peak of mechanical properties at 8h. By comparing the mechanical properties of the test steels after different aging treatments, the optimized heat treatment process of 10Ni2Cr2MnCuMoVAl steel is solution treatment at 880?? for 2h with air cooling and tempering temperature at 540?? for 4h with air cooling.     

Heat treatment,microstructure and mechanical properties of a metastable β titanium alloy timetal® 21s

Microstructure and mechanical properties of a metastable β titanium alloy were investigated in different heat treatment conditions. The alloy was melted by consumable vacuum arc melting followed by conventional forging and rolling. Microstructure and mechanical property evaluation were carried out in solution treatment and three different aging conditions. While low temperature aging resulted in increase in strength and decrease in ductility as compared to solution treatment condition, a double aging cycle provided considerably higher elongation values with a marginal increase in strength. Maximum fracture toughness was obtained in the double aging condition.     

Effect of Cooling Rate on Microstructure and Mechanical Properties of K465 Superalloy

 K465 superalloy, as a material for production of turbine nozzle, shows high mechanical properties as well as microstructure stability in critical and severe service conditions. The alloy gains its appropriate microstructure and strength through solid solution strengthening mechanism. Heat treatment parameters such as: time and temperature of homogenization, partial solution and aging temperatures, and cooling rate from solid solution affect the microstructure of the alloy. Among these parameters cooling rate from solid solution is the most effective. Therefore, in this study the effect of cooling rate on microstructure and mechanical properties (tensile and stress properties) were investigated. For this purpose, three different cooling rates were applied on the cast K465 specimens after solution treatment at 1210℃ for 4 h. Microstructures of the specimens then were studied using optical and electron microscopy. Also, tensile tests were performed at room temperature and stress rupture tests were performed under the condition of 975℃ and 230 MPa. It was found out that with increasing cooling rate the size of the γ' precipitates decreases and the mechanical properties of specimens increases. Also, it was shown that the shape and volume fraction of primary γ' particles are largely influenced by the cooling rate following solution treatment at 1210℃ for 4 h.     

时效温度对Custom 465钢力学性能的影响

 研究了经980 ℃固溶处理后再进行200~900 ℃热处理对Custom 465钢力学性能和奥氏体含量的影响。结果表明：为了使Custom 465钢的强韧性配合最佳,应进行适当的过时效处理,即在510~540 ℃温度区间进行时效处理。在450~480 ℃范围时效时,由于强烈的共格应变,导致Custom 465钢的韧塑性急剧下降,因此实际生产中应避免在该温度区间时效。实验结果证明,随时效温度升高,逆转变奥氏体是促使Custom 465钢韧性提高的原因之一。     

调整处理对0Cr17Ni4Cu4Nb不锈钢组织与力学性能的影响

实验室研究了调整处理工艺对0cr17Ni4Cu4Nb不锈钢组织与力学性能的影响,通过力学性能测试和金相显微组织观察,结果表明：随调整处理温度的提高,强度逐渐增加,塑性、韧性逐渐下降;816℃整处理后,随时效温度的提高,强度逐渐下降,塑性、韧性逐渐增加;在相同的时效温度下,与固溶态相比,调整处理后的强度显著较低但塑性、韧性较高。     

Design of the Precipitation Process for Ni-Al Alloys with Optimal Mechanical Properties: A Phase-Field Study

An attempt to design the heat treatment schedule for binary Ni-Al alloys with optimal mechanical properties was made in the present work. A series of quantitative three-dimensional (3-D) phase-field simulations of microstructure evolution in Ni-Al alloys during the precipitation process were first performed using MICRESS (MICRostructure Evolution Simulation Software) package developed in the formalism of the multi-phase field model. The coupling to CALPHAD (CALculation of PHAse Diagram) thermodynamic and atomic mobility databases was realized via TQ interface. Moreover, the temperature-dependent lattice misfits and elastic constants were utilized for simulation. The effect of the alloy composition and aging temperature on microstructure evolution was extensively studied with the aid of statistical analysis. After that, an evaluation function was proposed for evaluating the optimal heat treatment schedule by choosing the phase fraction, grain size, and shape factor of γ′ precipitate as the evaluation indicators. Based on 50 groups of phase-field-simulated and experimental microstructure information, as well as the proposed evaluation function, the optimal alloy composition, aging temperature, and aging time for binary Ni-Al alloy with optimal mechanical properties were finally chosen. The successful application in the present Ni-Al alloys indicates that it is possible to design the optimal alloy composition and heat treatment for other binary and even multicomponent alloys with optimal mechanical properties based on the evaluation function and the sufficient microstructure information. Additionally, the combination of the present method and the key experiments can definitely accelerate the material design and improve the efficiency and accuracy.     

Ti-Al-Mo合金的时效析出行为

研究了一种新型Ti-Al-Mo近β型钛合金在900℃×30 min/WQ固溶处理后,在不同条件时效处理后的析出相、显微硬度及力学性能。研究结果表明,在500℃时效4 h后的合金显微维氏硬度最高,为4 273 MPa;时效温度在400~700℃范围内时,随着时效温度的升高,析出的片层状α相尺寸逐渐增大,体积分数先增加后降低。由于加入了β稳定元素Mo,能提高强度但也会降低塑性,为了获得较好的强塑性匹配,在时效时间一定的前提下,时效温度应选取500℃左右;而为了得到较高的塑性和断裂韧性,在600~700℃之间时效较为适宜。     

燃气轮机用GH4720Li合金组织与性能关联性

基于光学显微镜、场发射电镜组织分析及系列力学性能测试,研究了固溶处理对燃气轮机用GH4720Li合金组织特征的影响,分析了组织特征与力学性能的关联性.结果表明:随着固溶温度的升高和固溶时间的增加,合金一次γ'相回溶,平均晶粒尺寸增加,当固溶温度高于1160℃,晶粒尺寸增大明显.GH4720Li合金的力学性能变化规律如下...     

双相区固溶温度对Ti-55531合金组织和力学性能的影响

通过对Ti-55531合金在双相区不同温度(730~830℃)固溶2 h空冷后,经相同的时效工艺(600℃/6 h/空冷(AC))处理;再结合扫描电子显微镜(SEM)和拉伸试验等分析方法,系统研究了双相区不同固溶温度对该合金组织和力学性能的影响规律。结果表明,随固溶温度的升高,等轴αp含量降低,尺寸减小;后续时效析出的αs含量增多,形态也有显著变化,由全短棒状向短棒状+针状、针状+长片状、全长片状的顺序转变。固溶温度从730℃升高到780℃,塑性较好的αp含量减少导致合金塑性降低,αs含量增加导致合金强度提高;固溶温度从780℃升高到800℃,αs含量继续增多导致合金强度上升,适量的长片状αs促进了合金塑性提高;固溶温度从800℃升高到相变点830℃,过多的长片状αs导致合金强度和塑性都显著下降。合金的强塑性匹配较好时对应的固溶温度为780~800℃。合金的断裂方式都是以微孔聚集型为主、含解理撕裂和沿晶开裂的混合断裂机制,且随固溶温度的增加,合金塑性断裂机制减小,脆性断裂机制增加。     

Influence of heat treatment parameters on structure and mechanical properties of an HSLA‐100 steel

An HSLA‐100 steel received from the US Naval Research Laboratory has been characterised. The effects of heat treatment parameters such as austenitisation time and temperature, tempering time and temperature on mechanical properties have been studied. The microstructures resulting from different heat treatment conditions have been correlated with mechanical properties through SEM and TEM studies. Quantitative relationships have been developed between mechanical properties and the operational variables within a narrow range of variation of the variables by statistical design of experiments. A quantitative relationship has also been developed for the same for a wider experimental region through curve fitting technique. The best combination of strength and low‐temperature toughness was obtained in the region of 700 °C tempering temperature and 0.3 ‐ 0.4 h tempering time.