共查询到20条相似文献,搜索用时 250 毫秒
1.
通过熔剂保护 ,在大气环境下制备了Mg RE中间合金 ,并制备了Mg MM Zn Zr ,Mg Nd Zn Zr和Mg Nd Y Zr 3种稀土镁合金 ,对合金分别进行了热处理 ,测量了各种状态下试验合金的硬度、抗拉强度及伸长率等力学性能 ,观察了合金的显微组织。结果发现 :含稀土元素Nd ,Y的试验合金有良好的热处理强化效果 ,其硬度和抗拉强度都高出常用的Mg MM Zn Zr合金。从过饱和固溶体中析出的细小弥散的含稀土元素强化相既可提高镁合金的强度 ,又可以提高镁合金的塑性 ,使合金由脆性断裂转化为韧性断裂 相似文献
2.
铸造Mg—RE—Zn—Zr合金的组织和性能 总被引:2,自引:0,他引:2
通过熔剂保护顺大气环境下制备了Mg-RE中间合金,并制备了Mg-MM-Zn-Zr,Mg-Nd-Zn-Zr和Mg-Nd-Y-Zr3种稀土镁合,对合金分别进行了热处理,测量了各种状态下试验合金的硬度、抗拉强度及伸长率等力学性能,观察了合金的显微组织。结果发现:含稀土元素Nd,Y的试验合金有良好的热处理强化效果,其硬度和抗拉强度都高出常用的Mg-MM-Zn-Zr合金。从过饱和固溶体中析出的细小弥散的含稀土元素强化相既可提高镁合金的强度,又可以提高镁合金的塑性,使合金由脆性断裂转化为韧性断裂。 相似文献
3.
4.
通过稀土Nd对ZM5合金改性研究,探讨了Nd以及热处理工艺对ZM5合金显微组织及腐蚀性能的影响.结果表明:随着Nd的加入,ZM5合金基体组织和第二相明显细化,显微组织有一定程度的改善;稀土Nd对ZM5合金的硬度影响不是很明显,ZM5+Nd与ZM5相比较,不同时效温度、时间与硬度关系曲线的起伏规律是相似的;稀土Nd的加入,减少了合金腐蚀贯穿性裂纹产生,降低ZM5合金腐蚀速率,提高合金抗腐蚀能力;固溶和时效处理对ZM5+Nd合金性能有很大的影响,合金经过适当时效处理后,硬度有所提高,抗腐蚀能力显著提高. 相似文献
5.
试验研究了稀土元素Nd对AM60镁合金组织、硬度和拉伸强度的影响。结果表明,随着钕含量的增加,合金的晶粒逐渐变小,硬度呈增加趋势,拉伸强度先增加后减小。当w(Nd)=0.6%时,合金的硬度达到最大值74 HV;当w(Nd)=0.45%时,合金的抗拉强度达到最大值230 N/mm2。 相似文献
6.
研究了稀土元素Y、Nd对AZ81镁合金组织和高温力学性能的影响.结果表明,稀土元素Y、Nd的加入明显细化了AZ81镁合金的显微组织,减少了β(Mg17Al12)相的析出.分析认为,稀土元素Y和Nd主要是通过固溶强化、析出强化和细晶强化提高了合金的室温和高温强度,改善了合金的塑性.复合加入2%的Y和Nd,合金的室温强度最高,达282.5MPa,与未加稀土的AZ81相比,约提高了39%.含1%Y的AZ81合金在150℃下的高温强度高达220 MPa,与不含稀土的AZ81相比高温强度约提高40%. 相似文献
7.
8.
Effect of Nd and Yb on the Microstructure and Mechanical Properties of Mg-Zn-Zr Alloy 总被引:1,自引:0,他引:1
研究了稀土元素Nd、Yb对Mg-5.5Zn-0.6Zr合金组织与性能的影响。结果表明:单独添加Nd或Yb元素后,试验合金的组织明显细化,同时在晶界处形成了γ((Mg,Nd)Zn2)或γ((Mg,Yb)Zn2)三元稀土相;而复合添加Nd和Yb元素后,试验合金的组织不但没有细化,而且在晶界处形成了呈网状分布的γ((Mg,Nd+Yb)Zn2)四元稀土相,并且晶界变宽。经过T4固溶处理后,Mg-5.5Zn-0.6Zr合金中的共晶组织完全溶入基体,而添加Nd、Yb元素后的Mg-5.5Zn-0.6Zr合金晶界处仍有未溶的化合物相存在。其中,添加Yb元素后的Mg-5.5Zn-0.6Zr合金经固溶处理后在晶界处形成了一种新的Mg-Zn-Yb三元球状颗粒相,其常温下的抗拉强度、屈服强度和伸长率分别达到了255.6 MPa、163.6 MPa和17.4%,这主要是因为加入稀土元素Yb后固溶处理产生了复合强化效果。在高温条件下,复合添加稀土元素Nb、Yb后的试验合金具有很好的热稳定性,但其高温塑性比较差。 相似文献
9.
研究了稀土元素Nd、Yb对Mg-5.5Zn-0.6Zr合金组织与性能的影响。结果表明:单独添加Nd或Yb元素后,试验合金的组织明显细化,同时在晶界处形成了γ((Mg,Nd)Zn2)或γ((Mg,Yb)Zn2)三元稀土相;而复合添加Nd和Yb元素后,试验合金的组织不但没有细化,而且在晶界处形成了呈网状分布的γ((Mg,Nd+Yb)Zn2)四元稀土相,并且晶界变宽。经过T4固溶处理后,Mg-5.5Zn-0.6Zr合金中的共晶组织完全溶入基体,而添加Nd、Yb元素后的Mg-5.5Zn-0.6Zr合金晶界处仍有未溶的化合物相存在。其中,添加Yb元素后的Mg-5.5Zn-0.6Zr合金经固溶处理后在晶界处形成了一种新的Mg-Zn-Yb三元球状颗粒相,其常温下的抗拉强度、屈服强度和伸长率分别达到了255.6 MPa、163.6 MPa和17.4%,这主要是因为加入稀土元素Yb后固溶处理产生了复合强化效果。在高温条件下,复合添加稀土元素Nb、Yb后的试验合金具有很好的热稳定性,但其高温塑性比较差。 相似文献
10.
11.
《Synthetic Metals》1998,96(3):177-189
Geometries of monomers through hexamers of cylopentadiene, pyrrole, furan, silole, phosphole, thiophene, selenophene and tellurophene, and monomers through nonamers of borole were optimized employing density functional theory with a slightly modified B3P86 hybrid functional. Bandgaps and bandwidths were obtained by extrapolating the appropriate energy levels of trimers through hexamers (hexamers through nonamers for borole) to infinity. Bandgaps increase with increasing π-donor strengths of the heteroatom. In general, second period heteroatoms lead to larger bandgaps than their higher period analogs. Polyborole is predicted to have a very small or no energy gap between the occupied and the unoccupied π-levels. Due to its electron deficient nature polyborole differs significantly from the other polymers. It has a quinoid structure and a large electron affinity. The bandgaps of heterocycles with weak donors (CH2, SiH2 and PH) are close to that of polyacetylene. For polyphosphole this is due to the pyramidal geometry at the phosphorous which prevents interaction of the phosphorus lone pair with the π-system. The bandgap of polypyrrole is the largest of all polymers studied. This can be attributed to the large π-donor strength of nitrogen. Polythiophene has the third largest bandgap. The valence bandwidths differ considerably for the various polymers since the avoided crossing between the flat HOMO — 1 band and the wide HOMO band occurs at different positions. The widths of the wide HOMO bands are similar for all systems studied. All of the polymers studied have strongly delecalized π-systems. 相似文献
12.
13.
Hiroaki Okamoto 《Journal of Phase Equilibria and Diffusion》2013,34(3):251-263
Recent literature on Cs-In, Cs-K, Cs-Rb, Eu-In, Ho-Mn, K-Rb, Li-Mg, Mg-Nd, Mg-Zn, Mn-Sm, O-Sb, and Si-Sr phase diagrams is reviewed in this article in order to update the 1990 compilation Binary Alloy Phase Diagrams, 2nd edition, by T.B. Massalski, et al. For some systems reaction tables and crystal structure data have been included, as well. Diagrams have been checked for consistency with rules for phase diagram construction and modified when necessary. In addition, diagrams needing more work have been identified. 相似文献
14.
15.
16.
17.
18.
19.
20.
Hiroaki Okamoto 《Journal of Phase Equilibria and Diffusion》2013,34(4):350-362
Recent literature on Bi-Ce, Bi-Er, C-Ce, C-La, C-Pr, Cd-I, Cr-Cu, Cu-Er, Er-Sb, F-Sm, F-Yb, and Fe-Gd phase diagrams is reviewed in this article in order to update the 1990 compilation Binary Alloy Phase Diagrams, 2nd edition, by T.B. Massalski, et al. For some systems reaction tables and crystal structure data have been included, as well. Diagrams have been checked for consistency with rules for phase diagram construction and modified when necessary. In addition, diagrams needing more work have been identified. 相似文献