一种高强变形高温合金性能优化研究

IMR OpenIR

	一种高强变形高温合金性能优化研究
	张磊
学位类型	硕士
导师	孙文儒
	2011
学位授予单位	中国科学院金属研究所
学位授予地点	北京
学位专业	材料学
关键词	高温合金热处理制度 b w Superalloy Heat Treatment b w
摘要	"高温合金是制造航空发动机等高温部件的关键材料。随着发动机的发展，高温合金需要具有更高热强性。本文研究了一种高强镍基高温合金的组织和性能，并通过改变热处理制度探索该合金性能优化方法，初步研究了B对合金凝固、组织和性能的影响，为该合金的应用提供依据。组织分析表明合金中除析出γ′相外，还析出α-W，μ相， MC，M6C和M23C6。α-W呈颗粒状分布于晶内，μ相呈块颗粒状断续分布于晶界和晶内。MC相呈块状分布于晶界，M6C相在其周围析出，细碎M23C6相在晶界析出。g′相析出峰温度为850℃。m相析出温度范围为850～1150℃，析出峰温度在1000℃附近。晶界M23C6相析出温度范围在750～1050℃。拉伸性能测试表明合金具有较高的热强性，在室温到650℃范围内，合金的抗拉强度和屈服强度随温度上升缓慢降低。当温度高于650℃，合金的抗拉强度和屈服强度随温度的升高快速下降。同时合金存在中温脆性现象，在750～850℃下，合金的延伸率仅为5%左右。热处理实验和拉伸性能测试表明μ相对合金力学性能的影响与温度有关，750℃以下，μ相主要起第二相强化作用，提高合金拉伸强度，降低拉伸塑性；950℃下，μ相析出消耗较多固溶强化元素W，降低拉伸强度，提高拉伸塑性。固溶温度对合金硬度值和拉伸性能影响不大。时效制度对合金的硬度值和力学性能产生明显的影响。在1130℃×1h，WC+900℃×4h，AC+700℃×6h，AC处理下合金强度和塑性得到合理的搭配。铸态组织分析表明B细化枝晶组织，抑制了凝固过程中η相析出，改变MC相析出形态，使其由条状向块状转化。热压缩实验表明B降低了合金的热加工温度，抑制变形过程中颗粒状μ相的析出。但其对合金性能的影响需要进一步的研究。"
其他摘要	"Superalloy is Widely used as critical materials in the fabrication of high temperature components, such as aeroengine. With the development of aeroengine, superalloy should have higher strength. The microstructure and properties of a high strength nikle-base superalloy and methods of performance optimization are investigated by changing the heat treatments, the influence of the B on the solidification, microstructure and properties of the alloy is also initially investigated in this paper for the sake of application. The microstructure analysis indicates that in addition of γ′ in the alloy, there are also minor phases are μ, α-W, MC, M6C, M23C6. A few α-W particles precipitate inside the grain. μ particles precipitates along the grain boundaries or inside the grain. MC particals precipitate along the grain boundaries, with M6C particals around them. Fine M23C6 particles precipitate along the grain boundaries. The precipitation of γ′ reaches its peak at 850℃. The precipitation of μ phase is firstly increased and then decreased in the range from 850℃ to 1150℃, with its peak around 1000℃.And M23C6 phase precipitates in the range from 750℃ to 1050℃. The tensile tests were carried out in the range of 20～1000 ℃. The results show that both yield and tensile strengths decrease slightly with increasing temperature to 650 ℃, then decrease sharply when the temperature is higher than 650 ℃.The elongation has its minimum value (about 5%) at intermediate temperature(750 ～850 ℃). Heat trearments and tensile tests show that the effect of μ phase on the alloy is related with temperature, it strengthens the alloy by impeding the motion of dislocations and increases the yield and ultimate strength at room temperature up to 750℃, and slightly decreases the elongation. While it deceases the yield and ultimate strength and increases the elongation of the alloy at 950℃, because its precipitation consumes the solid strengthening element W which is the main strengthening form when the g¢ phase is totally dissolved. The effect of solution temperature on the hardness and tensile properties is little, While the effect of aging treatment is prominent. The strength and ductile of the alloy are reasonable collocation at 1130 ℃×1h, WC + 900 ℃ × 4h, AC + 700 ℃ × 6h, AC. The microstructure analysis of the ingot indicates that addition of element B refine the microstructure of the dendritic, restrain the precipitation of η phase in the solidification and change the precipitate morphology of MC from long trips to particles. Hot deformation tests indicate that element B decrease the hot-working temperature, and hinder the precipitation of μ phase during the deformation. But the effect of elment B on the properties of the alloy need furtherly study."
文献类型	学位论文
条目标识符	http://ir.imr.ac.cn/handle/321006/64406
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	张磊. 一种高强变形高温合金性能优化研究[D]. 北京. 中国科学院金属研究所,2011.