共查询到19条相似文献,搜索用时 31 毫秒
1.
2.
通过对40Cr,T10钢的同材或异材恒温超塑焊接接头的断口分析,提出超塑焊接接头是由冶金结合的焊合区及机械结合区、显微空隙等焊接缺陷构成的接头构成模型,可供超塑焊接工艺及质量检测参考。 相似文献
3.
4.
介绍了用于大型构件超塑成形的加热及换模装置的主要结构特点。该装置能够满足大尺寸铝、钛合金板材超塑成形和扩散连接的需要 相似文献
5.
介绍了用于大型构件超塑成形的加热及换模装置的主要结构特点。该装置能够满足大尺寸铝、钛合金板材超塑成形和扩散连接的需要。 相似文献
6.
焊接刀具超焊缝加热淬火工艺研究 总被引:2,自引:0,他引:2
本文对W18Cr4V钢、45钢摩擦焊焊接刀具进行了超焊缝加热淬火工艺研究。结果表明,超焊缝加热淬火回火,焊缝组织得到改善,硬度、抗弯强度及扭转强度均得到提高、焊缝处未产生裂纹。超焊缝加热淬火工艺具有很多优点,应进行深人研究。 相似文献
7.
8.
9.
详细介绍了电炉炼钢用石墨电极柱侧面防氧化涂层的特点及开发过程。所开发的电极防氧化涂料可以在1300℃下对石墨电极起到防氧化作用。 相似文献
10.
11.
12.
Hot isothermal/isostatic pressing machines are technically good candidates for superplastic forming (SPF) of otherwise hard-to-shape
materials such as superalloys. These machines are, however, very expensive so that small or medium-size enterprises can not
afford them. This has impeded widespread use of SPF processing. In an attempt to alleviate the problem, the authors have developed
a laboratory model of an affordable hot isothermal pressing machine with differential gas pressure as the forming medium.
Careful selection of process parameters such as temperature, gas pressure, strain rate, and process time as well as monitoring
of thickness changes in a workpiece has a pivotal role in successful operation of such machine. It has been illustrated in
this article that SPF can be successfully performed with this machine on the basis of process parameters estimated with existing
analytical relations. The performance of this machine has been verified by several experiments on SPF of titanium-based sheets,
as reported in this article. 相似文献
13.
14.
基于Gleeble等温热压缩试验,并结合OM、SEM、EBSD等分析手段,研究了一种新型热挤压态第3代镍基粉末高温合金FGH4113A(WZ-A3)在超塑性压缩变形过程中的流动特性和微观组织演化规律。给出了在温度1050、1100℃,应变速率0.001、0.005 s-1,不同变形量(应变)条件下的超塑性变形行为及其变形机制。结果表明:FGH4113A(WZ-A3)合金在热压缩变形过程中表现出良好的超塑性,未发现孔洞或裂纹;1100℃/0.001 s-1大变形后期(60%~80%变形量)晶粒有长大趋势,其余变形条件晶粒尺寸变化不大;在超塑性压缩变形过程中,累积的位错主要通过动态回复和动态再结晶所湮灭,晶界滑移是发生大变形而未开裂的主要原因。该研究结果为新型的FGH4113A(WZ-A3)合金超塑性等温锻造工艺制定奠定了良好的基础。 相似文献
15.
超塑成形是制造难变形材料复杂零部件的一种精密成形技术,超塑成形设备通过温度加热和测控系统以及成形速度和压力控制系统,使特殊材料在温度和气压作用下发生超塑变形。 相似文献
16.
17.
H. T. Mallikarjuna N. L. Richards W. F. Caley 《Journal of Materials Engineering and Performance》2017,26(5):2014-2023
Ni-based superalloys are used for high-temperature components of gas turbines in both industrial and aerospace applications due to their ability to maintain dimensional stability under conditions of high stress and strain. The oxidation resistance of these alloys often dictates their service lifetime. This study focuses on the isothermal oxidation behavior of three Ni-based superalloys, namely, polycrystalline cast IN738LC, single-crystal N5, and a ternary Ni-Fe-Cr (TAS) powder metallurgy alloy. The isothermal oxidation tests were conducted at 900 °C in the static air up to 1000 h, and the specific aspects studied were the oxidation behavior of these chromia-forming and alumina-forming alloys that are used extensively in industry. In particular, the behavior of oxide scale growth and subsurface changes were analyzed in detail using various techniques such as SEM, EDS, and AFM. From the isothermal oxidation kinetics, the oxidation rate constant, k p, was calculated for each alloy and found to be; k p = 2.79 × 10?6 mg2 cm?4 s?1 for IN738LC, k p = 1.42 × 10?7 mg2 cm?4 s?1 for N5 and k p = 1.62 × 10?7 mg2 cm?4 s?1 for TAS. Based on a microstructural analysis, IN738LC exhibited a continuous dense outer scale of Cr2O3 and discontinuous inner scale of Al2O3, whereas N5 and TAS showed a dense outer scale of Al2O3 alone. The results suggested that the N5 and PM-TAS alloys are more oxidation resistant than the IN738LC under these conditions. 相似文献
18.
目的系统地评价典型高温防护涂层的抗高温氧化性能,并分析其失效机制。方法通过对比普通Ni Al涂层、NiCrAlY涂层、Pt改性Ni Al涂层以及Pt+Hf共改性Ni Al涂层等四种典型高温防护涂层在1100℃的恒温氧化行为,从氧化过程中的氧化增重、组织结构演变规律等角度出发,分析了四种涂层在高温氧化过程中的抗氧化性能以及氧化失效规律。结果四种涂层在1100℃恒温氧化过程中的增重均符合抛物线规律。普通Ni Al涂层氧化膜粘附性能较差,氧化膜快速剥落,涂层退化最快。NiCrAlY涂层中Y元素在氧化膜/涂层界面形成"钉扎"作用,显著提高氧化膜的粘附性能,但由于涂层内部Al元素含量降低,涂层1100℃氧化300 h后基本失效。Pt改性Ni Al涂层的氧化膜较为完整,但氧化膜起伏严重。Pt+Hf共改性Ni Al涂层的氧化膜均匀完整且无明显起伏,具有综合最优的抗高温氧化性能。结论四种涂层的抗高温氧化性能排序为:Pt+Hf共改性Ni Al Pt改性NiAl普通Ni AlNiCrAlY。 相似文献
19.
研究了Ag-Sn合金内氧化热力学与恒温氧化行为。热力学计算结果表明,Ag-Sn合金内氧化在热力学上是可行的,并绘制了合金氧化热力学区位图。经氧化实验获得Ag-Sn合金恒温氧化行为曲线。Ag-Sn合金快速氧化的温度区间为550℃至800℃。随内氧化温度的升高,合金的氧化更为彻底并逐步趋于平稳。实验所得AgSnO2材料中,SnO2颗粒弥散分布于Ag基体中。在内氧化过程中,氧的扩散使合金内部发生氧化,并生成呈网状排布的氧化物。 相似文献