对于17-4PH钢超大型锻件而言,其成分宏观偏析、缩孔疏松、碳化物析出、裂纹的产生以及晶粒度的大小通常难以控制,从而严重影响其力学性能和后续的产品使用。以28 t 17-4PH钢电渣锭从生产至获得成品的生产为例,从对重熔渣系设计、锻造工...对于17-4PH钢超大型锻件而言,其成分宏观偏析、缩孔疏松、碳化物析出、裂纹的产生以及晶粒度的大小通常难以控制,从而严重影响其力学性能和后续的产品使用。以28 t 17-4PH钢电渣锭从生产至获得成品的生产为例,从对重熔渣系设计、锻造工艺流程以及固溶时效热处理等重点工艺入手,优化了产品制造过程,特别通过精确控制固溶和时效工艺,在350~1050℃范围内分步加热保温固溶处理以及150~530℃范围内多次加热保温时效处理,成功控制了产品中残余奥氏体、富铜相及弥散析出相的体积分数,达到了可控的基体晶粒度,有效抑制了不利相的析出,同时显著降低了工件的内部应力及开裂风险。通过优化措施不仅保证了产品的力学性能,而且显著延长了其使用寿命,有效解决了该领域中的多项技术难题。展开更多
We investigate computationally the attenuation and reflection of Terahertz （THz） wave using targets coated with plasmas. The simulators are the Wentzel-Kramer-Brillouin （WKB） method and finite-difference timedoma...We investigate computationally the attenuation and reflection of Terahertz （THz） wave using targets coated with plasmas. The simulators are the Wentzel-Kramer-Brillouin （WKB） method and finite-difference timedomain （FDTD） method. The relation between the frequency of the incident electromagnetic （EM） wave and the attenuation caused by unmagnitized plasma is analyzed. The results demonstrate that the amount of absorbed power is a decreasing function of the EM wave frequency and the plasma collision frequency. For THz band incident wave, the attenuation that is caused by plasma is small when the plasma has common density and the collision frequency. This conclusion has fine applying foreground for plasma anti stealth.展开更多
文摘对于17-4PH钢超大型锻件而言,其成分宏观偏析、缩孔疏松、碳化物析出、裂纹的产生以及晶粒度的大小通常难以控制,从而严重影响其力学性能和后续的产品使用。以28 t 17-4PH钢电渣锭从生产至获得成品的生产为例,从对重熔渣系设计、锻造工艺流程以及固溶时效热处理等重点工艺入手,优化了产品制造过程,特别通过精确控制固溶和时效工艺,在350~1050℃范围内分步加热保温固溶处理以及150~530℃范围内多次加热保温时效处理,成功控制了产品中残余奥氏体、富铜相及弥散析出相的体积分数,达到了可控的基体晶粒度,有效抑制了不利相的析出,同时显著降低了工件的内部应力及开裂风险。通过优化措施不仅保证了产品的力学性能,而且显著延长了其使用寿命,有效解决了该领域中的多项技术难题。
基金the National Natural Science Foundation of China (60771017)the China Postdoctoral ScienceFoundation (20060390272)
文摘We investigate computationally the attenuation and reflection of Terahertz （THz） wave using targets coated with plasmas. The simulators are the Wentzel-Kramer-Brillouin （WKB） method and finite-difference timedomain （FDTD） method. The relation between the frequency of the incident electromagnetic （EM） wave and the attenuation caused by unmagnitized plasma is analyzed. The results demonstrate that the amount of absorbed power is a decreasing function of the EM wave frequency and the plasma collision frequency. For THz band incident wave, the attenuation that is caused by plasma is small when the plasma has common density and the collision frequency. This conclusion has fine applying foreground for plasma anti stealth.
