共查询到20条相似文献,搜索用时 0 毫秒
1.
熔炼配制了Mg-Al-Ca-Mn合金,采用单轴拉伸实验测试了合金在25~475℃温度范围内的应力-应变曲线,通过数据处理分析了其加工硬化率曲线,并采用显微组织观察研究了不同形变温度下合金的形变机制。研究表明,合金拉伸的应力-应变曲线在不同温度下存在明显区别,且取决于其形变机制的不同。室温变形的形变机制以孪生为主,应力随应变增加而快速增加至最大值后断裂,塑性较差。425℃高温变形时主要形变机制为动态再结晶,应力在变形初期的极小应变范围内迅速达到最大值,由于动态再结晶的软化作用,应力值缓慢减小,表现出良好的变形能力。而当形变温度处于中温区(225℃)时,加工硬化阶段以孪生变形为主,随着应变的不断增加,部分区域发生动态再结晶,应力增加至最大值后缓慢减小,直到断裂。 相似文献
2.
3.
《中国有色金属学会会刊》2006,16(A03):1279-1284
4.
对6014铝合金进行了常温拉深试验,采用不同的拉深凸模速度,研究了该铝合金变形中的组织力学行为;对6016铝合金进行热拉伸试验,相同应变速率下采用不同的拉伸温度,研究了该铝合金在热拉伸过程中的组织力学行为。实验表明:随着凸模速度(10~30 mm·min~(-1))增加,6014铝合金的常温拉深深度增大;随着拉伸温度(400~550℃)升高,6016铝合金的硬度增大,且沿拉伸轴向硬度值波动越大;在应变速率为1 s~(-1)、温度为500℃下热拉伸,变形区有明显的动态再结晶过程,进一步升高温度会造成再结晶组织的晶粒粗化;6014和6016铝合金中均存在大量的Al、Fe、Si结晶相,但原始组织中6016的析出相更弥散,尺寸大小更均匀,更集中分布于晶界附近;比较6014铝合金常温拉深组织和6016铝合金热拉伸组织,冷变形后的晶粒组织更均匀,热拉伸后的晶粒尺寸差异很大,会降低材料变形后的力学性能。 相似文献
5.
不同焊接工艺下2219铝合金TIG焊接头性能分析 总被引:2,自引:0,他引:2
针对2219铝合金的对接TIG焊,采用单面两层焊和两面三层焊的工艺方法开展了对比试验,分析了焊接接头形貌和组织性能。研究结果表明,两种工艺方法均可以获得良好的焊缝成形,力学性能满足结构设计要求;两面三层焊比单面两层焊的焊接接头抗拉强度和断后伸长率的平均值分别提高了1.7%和33.3%,抗拉强度基本相同,断后伸长率得到了大幅提升;相比于单面两层焊,两面三层焊的背部封底焊接增加了背部焊缝宽度,背部熔合线的形状以及与水平方向的夹角都发生了变化;两种工艺方法的焊接接头各区域组织特点鲜明,相同区域的微观形貌相差不大;在焊缝背部相同位置,两种工艺方法的硬度值曲线走向趋势相同,封底焊增大了过时效软化区的宽度,提高了焊接接头的断后伸长率。 相似文献
6.
He-Ning Liu Kui Zhang Xing-Gang Li Yong-Jun Li Ming-Long Ma Guo-Liang Shi Jia-Wei Yuan Kai-Kun Wang 《稀有金属(英文版)》2021,(3):643-650
The cooling gradient of Mg-3Zn-1Ca-0.5Sr alloy in cast ingots under different cooling methods (air cooling,warm-water cooling and ice-water-mixture cooling) was... 相似文献
7.
8.
强冷条件下铝合金的变形行为 总被引:2,自引:1,他引:2
通过热模拟实验研究了铝合金在强冷条件下的变形行为和显微组织。结果表明,所得到的铝合金组织主要是树枝晶。树枝晶组织的凝固过程对外力施加的应变速率很敏感,ε·=0.10s-1是变形与凝固过程开始发生耦合作用的临界点。低于此值,变形对凝固过程无影响;高于此值时,变形作用于凝固过程,枝晶发生弯曲或断裂,凝固组织发生改变。随变形速率的增大,合金组织由枝晶密排的变形组织向破碎的枝晶组织转化,枝晶发生球化。应变速率越大,变形抗力越小,晶粒越细小,晶粒的球化特征越明显。 相似文献
9.
《中国有色金属学会会刊》2020,30(4):835-849
2195 Al-Li alloy was deformed through extrusion followed by cold-rolling. The textures of the extruded plate and cold-rolled sheet after solutionization were investigated. The longitudinal strength and precipitates after T8 aging were measured and observed, respectively. Compared to those in the sheet, T1(Al2CuLi) precipitates in the extruded plate after T8 aging are non-uniform, and their incubation time is shorter. The extruded plate after solutionization is not recrystallized and contains 55.28% deformation textures of Brass and S. In the cold-rolled sheet after solutionization, massive recrystallization occurs and S component disappears. Due to the higher fraction of Brass and S textures with higher Schmid factor and lower equivalent sliding system number, the extruded plate possesses an yield strength not higher or even lower, but a tensile strength higher, than the cold-rolled sheet after solutionization. In addition, during the aging after pre-stretch, these textures promote T1 precipitation on preferred sliding planes of cold-rolled sheet and cause its higher yield strength and tensile strength after T8 aging. 相似文献
10.
11.
The current paper explains the corrosion characteristics of the titanium alloy, IMI-834 in three different environments which simulates acidic, marine and industrial environments at various temperatures. The titanium alloy forms a protective oxide scale under different environmental conditions at lower temperatures. However, they do not form a protective oxide scale at higher temperatures. The corrosion rate in different environments and at different temperatures increases by about five times in acidic and industrial environments when the temperature increases by a factor of 2. While in marine environments, the corrosion rate was found to increase by two times when the temperature increases by two times. The pitting corrosion studies in different environments revealed that the alloy is resistant to pitting and crevice corrosion at lower temperatures but is susceptible at higher temperatures. The corrosion morphologies were correlated and the degradation mechanism that is leading the titanium alloy to fail under various environmental conditions was discussed. Finally, based on the results obtained with different techniques, the alloy was recommended to fabricate components intended to use in a variety of environmental conditions. 相似文献
12.
13.
14.
The solution to the problem of improving the mechanical properties (including cyclic strength) of structural materials is largely dependent on our knowledge of the laws governing the development of microplastic deformations in them. The effect of heat and mechanical treatment on the elastoplastic properties and fatigue resistance of the commercial aluminum alloys AK4-1 and D16 is analyzed.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 27 – 31, February 1995. 相似文献
15.
16.
通过压缩锥形试样研究了温度和变形程度对GH738合金微观组织的影响,分析了不同变形程度下,合金的再结晶晶粒尺寸、再结晶体积分数和平均晶粒尺寸的演化情况,为制定GH738合金热态变形工艺提供了理论依据。研究结果表明,随着温度升高,再结晶晶粒尺寸变大;随变形程度减小,再结晶体积分数逐渐减小。在不同变形程度下,在1120℃温度时变形可获得较高的再结晶体积分数和较均匀的再结晶晶粒尺寸;当加热温度1100~1140℃范围内,变形程度大于28%时,可以获得晶粒尺寸较为均匀的微观组织。 相似文献
17.
18.
19.
《金属热处理》2015,(9)
研究了不同退火工艺对TC4合金力学性能的影响。结果表明,经普通退火的TC4合金的短时力学性能要明显好于经β退火的TC4合金,其抗拉强度高出约100 MPa,屈服强度高出约80 MPa,伸长率高出约60%。经β退火后的TC4合金的断裂韧度为100~120 MPa·m1/2,而普通退火态的TC4合金仅有80~90 MPa·m1/2。分析表明,经普通退火得到的显微组织比经β退火处理得到的篮网组织有着更好的强度和塑性,而篮网组织可以使裂纹扩展路径变长,显著提高了TC4合金的断裂韧度值。同时,得到了TC4合金屈服强度与断裂韧度值的函数表达式,发现TC4合金的屈服强度与断裂韧度值的平方成反比。采用此函数关系表达式计算出的KIC值在KIC的实测值范围内,为TC4合金断裂韧度检测结果的可靠性提供了一种判断方法。 相似文献