共查询到20条相似文献,搜索用时 234 毫秒
1.
2.
为了提高4043铝合金焊丝堆焊层的耐磨性,在传统4043铝合金焊丝成分基础上,添加Mg与变质剂Sr,对Al-Si-Mg-Sr合金焊丝焊后堆焊层进行热处理,研究了Mg、Sr以及热处理工艺对焊丝焊后堆焊层耐磨性的影响。结果表明,在4043铝合金焊丝中添加变质剂Sr可以改变堆焊层组织中共晶硅颗粒的形态;Mg可以为堆焊组织增加强化相Mg2Si;合理的热处理工艺可以球化共晶硅颗粒,增强共晶硅颗粒与基体的结合能力;三者的共同作用可以显著提高焊丝堆焊层的耐磨性。 相似文献
3.
《特种铸造及有色合金》2016,(1)
以铸态Mg-7Al-1Si合金为基体,单独添加变质剂Gd及复合添加变质剂Gd与Ca,对比研究不同变质剂对铸态Mg-7Al-1Si合金组织及性能的影响。结果表明,单一添加变质剂Gd及复合添加变质剂Gd与Ca均能明显细化Mg-7Al-1Si合金的晶粒尺寸,β-Mg_(17)Al_(12)相细小弥散且含量降低。单一添加Gd及复合添加Gd与Ca后,蠕变应变量分别降低了69.3%、80.7%。复合添加Gd与Ca后,合金的抗高温蠕变性能比单独加入稀土元素Gd时更好。变质剂Gd与Ca有效改善了Mg-7Al-1Si合金的摩擦磨损性能。 相似文献
4.
添加Cu及(Ti+B)对ZA12组织和性能的影响 总被引:1,自引:0,他引:1
通过研究Cu及(Ti+B)变质剂对ZA12合金组织结构的作用,分析Cu及(Ti+B)变质剂对合金力学性能的影响。结果表明,随着Cu添加入量的增加,合金强度和硬度提高,塑性和韧性下降。变质剂(Ti+B)对合金组织和性能有明显的影响。 相似文献
5.
6.
在LM28(过共晶铝硅合金)熔炼过程中分别添加变质剂P、P+Na盐、P+Na盐+RE对合金进行变质处理,分析了不同变质剂对合金力学性能与微观组织的影响.结果表明,P、Na盐和RE都是以改变硅相的生长状况使Al-Si合金发生变质的,其中P主要变质初晶硅,Na盐和RE主要变质共晶硅.试验证明加入复合变质剂P+Na盐+RE后的LM28合金铸态组织相对最好,力学性能最高. 相似文献
7.
改变Ti或Nb的添加量制备Fe-Cr-C-B系铁基堆焊合金.借助扫描电镜、X射线衍射仪、洛氏硬度计和磨损试验机对堆焊合金组织性能进行测试分析.结果表明,在含Ti或Nb的堆焊合金中,初生奥氏体晶粒细化,共晶组织呈断网状均匀分布,并分别有黑色圆形或块状TiC和菱形或三角形NbC硬质相颗粒生成,添加5%Ti的堆焊合金组织最细小.TiC或NbC硬质相颗粒在组织中呈均匀弥散分布,能够作为耐磨质点与细化的初生奥氏体和共晶组织构成耐磨骨架,共同抵抗磨粒的楔入与切削作用.当Ti添加量为5%时,含Ti堆焊合金达到最优耐磨性,硬度为66 HRC,磨损量为0.048 7 g;当Nb添加量为4%时,含Nb堆焊合金达到最优耐磨性,硬度为65 HRC,磨损量为0.052 4 g.在同等条件下,含有适量Ti的铁基堆焊合金具有更优的耐磨性. 相似文献
8.
通过对轧辊用高速钢进行复合变质及热处理。探讨了含碱金属K/Na以及V、Mo合金元素的变质剂的加入量对轧辊用铸造高速钢共晶组织的影响。试验结果表明:在1.0%范围内,随着复合变质剂含量的逐渐增加,共晶碳化物的形貌和分布得到了改善,晶粒得到细化,分布趋于均匀,轧辊用高速钢的硬度略有下降,但韧性有很大提高。变质剂含量继续增加,组织和性能没有明显改善。进一步分析表明:变质剂中的合金元素可促进在晶粒中或沿晶界均匀分布的非连续状硬质碳化物的生成.从而达到改善组织、提高力学性能的作用。 相似文献
9.
10.
采用DJ5003堆焊焊条在45钢表面制备了不同堆焊层数的合金,使用OM,SEM,显微硬度计、磨损试验机等设备对堆焊金属的组织性能进行了测试分析。研究表明,堆焊接头冶金结合良好,DJ5003焊条堆焊合金的显微组织由马氏体、残余奥氏体和碳化物等组成,随着堆焊层数的增加,堆焊层金属中马氏体和碳化物越来越细小、数量越来越多,且分布更均匀;堆焊层金属的显微硬度明显高于基体材料,且随着堆焊层数的增加,基体材料的稀释作用越来越小,堆焊层金属的硬度逐渐增高,而磨损量显著降低,当堆焊3层时,堆焊层金属的平均显微硬度达到HV776.4,而磨损量仅为0.303 g,磨痕犁沟最浅,耐磨性最好。 相似文献
11.
LIUYan-xia MAYong-qing WANGYue-hua ZHANGZhan-ping ZHANGYang 《材料热处理学报》2004,25(5):631-634
The changes of tempering microstructure and properties of Fe-Cr-V-Ni-Mn-C cast alloys with martensite matrix and much retained austenite are studied. The results showed that when tempering at 200℃ the amount of retained austenite in the alloys is so much that is nearly to as-cast, and a lot of retained austenite decomposes when tempering at 350℃ and the retained austenite decomposes almost until tempering at 560℃. When tempering at 600℃, the retained austenite in the alloys all decomposes. At 560℃ the hardness is highest due to secondary hardening. The effect of nickel and manganese on the microstructure and properties of Fe-Cr-V-C cast alloy were also studied. The results show that the Fe-Cr-V-C cast alloy added nickel and manganese can obtain martensite matrix and much retained austenite microstructure, and nickel can also prevent pearlite transformation. With the increasing content of nickel and manganese, the hardness of as-cast alloy will decreases gradually, so one can improve the hardness of alloy by tempering process. When the content of nickel and manganese is 1.3~1.7%, the hardness of secondary hardening is the highest (HRC64). But when the content of nickel and manganese increase continually, the hardness of secondary hardening is low slightly, and the tempering temperature of secondary hardening rises. 相似文献
12.
采用等离子熔覆技术制备了四种不同铬含量的Fe-Cr-B-C堆焊合金.借助OM,SEM和XRD等分析手段对合金组织和陶瓷相形貌进行分析.结果表明,熔覆层的微观组织由初生奥氏体+共晶组织组成,合金陶瓷相由BC4+Cr2B+M7C3+M23C6+M23(C,B)6组成,硼化物呈层片状、菊花状等形态分布,陶瓷相数量随Cr元素含量的增大而增多.研究了Cr元素含量对熔覆层耐磨粒磨损性能的影响规律,熔覆层的耐磨性随着Cr元素含量的增加而提高,当Cr元素含量达到15.9%时,大量硼化物等陶瓷相弥散分布在基体中,构成良好的耐磨骨架;初生奥氏体组织均匀分布提高硬质相与基体界面的结合强度,因此其熔覆层具有最佳的耐磨性. 相似文献
13.
Yingcai Liu Weifeng Wei Les Benum Mike Oballa Mike Gyorffy Weixing Chen 《Oxidation of Metals》2010,73(1-2):207-218
The oxidation behavior of Ni–Cr–Fe-based alloys in a low oxygen partial pressure atmosphere (H2–H2O) was investigated in terms of the effect of alloy microstructure and their silicon content. It was found that the formation and growth kinetics of the oxide scale are rather sensitive to the alloy microstructure and their corresponding Si contents. Oxide ridges were found to form in areas with eutectic structure, while a thin and homogeneous oxide scale formed on austenite matrix. The thicknesses of the oxide ridges and the oxide layer on the austenite matrix were dependent of their corresponding Si contents. The austenite/carbide phase boundaries in eutectic structure can offer fast diffusion paths for metal outward diffusion, which leads to the formation of ridge-like oxide features. The continuous SiO2 sub-layer formed at the oxide scale/metal interface on the austenitic matrix acted as an effective diffusion barrier to metal outward diffusion, resulting in rather thin and uniform oxide scales. 相似文献
14.
借助光学显微镜(OM)、扫描电镜(SEM)、X射线衍射分析仪(XRD)和洛氏硬度计等,研究了I&Q&P工艺对高硼铁基耐磨合金组织和性能的影响。结果表明,高硼铁基合金的铸态组织由铁素体、马氏体、残留奥氏体和共晶硼化物组成,硼化物主要为Fe2B和Fe23(B,C)6。经I&Q&P工艺处理后,合金中残留奥氏体的体积分数从10.0%上升到16.8%,冲击吸收能量从3.76 J增加到6.80 J,硬度值从59.3 HRC下降至54.0 HRC,并生成了新的硼化物Fe3(B,C)。同时,合金的耐磨性也有了明显的提高。 相似文献
15.
《Acta Materialia》2003,51(10):2921-2932
Application of a magnetic field during the ferrite to austenite transformation in Fe–C alloys was found to yield a two-phase microstructure with the paramagnetic austenite grains aligned as chains or columns along the direction of the field in the matrix of ferromagnetic ferrite phase. The underlying mechanism of dipolar interactions suggests that similar alignment of microstructures should take place during the austenite to ferrite transformation under a magnetic field. In the present investigation, an experimental setup has been designed to study the magnetic alignment. Its concept is characterized by deforming steels prior to the austenite to ferrite transformation to introduce ample nucleation sites in addition to applying magnetic fields up to 12 T. Experiments have revealed successful conditions for aligned two-phase microstructures in carbon steels. The formation mechanism of the aligned structures is discussed from the viewpoint of the nucleation and growth of ferrite grains in austenite phase under a magnetic field. Furthermore, it is shown that the shape of the aligned ferrite grains is determined by a balance of the magnetostatic and the interfacial energies. 相似文献
16.
17.
This experiment investigated the role of chromium in the mechanical properties of Fe-5Mn-9Ni-5Mo-1.5Ti maraging steels containing up to 3% chromium. Remarkable age-hardening responses were observed in the Fe-5Mn-9Ni-5Mo-1.5Ti and Cr-bcaring alloys. A ductile-brittle-ductile transition occurred in the Cr-bearing alloys during isothermal aging below 510°C. This was due to the segregation of titanium and manganese to prior austenite grain boundaries and their subsequent desegregation into the matrix. The addition of chromium to the base alloy considerably improved its ductility after aging at 520°C. From microstructure and AES analyses, it is suggested that chromium addition augments the volume fractions of (Fe,Mn)2Mo and η-Ni3Ti precipitates in the Fe-5Mn-9Ni-5Mo-Cr alloys, which act as sinks of manganese and titanium in the matrices. This resulted in the reduction of the alloying elements concentration in the matrix, which is followed by the reduction in the segregation level of the elements at prior austenite grain boundaries, and consequently enhanced intergranular fracture strength. The optimum combination of strength and ductility was obtained in the Fe-5Mn-9Ni-5Mo-3Cr-l.5Ti alloy aged at 520°C for 2 hr. and was σ0 2=1721 MPa, σLS=1756 MPa. and ε,= 10.2%. 相似文献
18.
Hua Ding Dong Han Zhihui Cai Zhiqiang Wu 《JOM Journal of the Minerals, Metals and Materials Society》2014,66(9):1821-1827
In the present work, two Fe-18Mn-10Al-xC low-density steels with different C concentrations were investigated. It is revealed that the difference in C concentration resulted in a marked difference in the microstructures of the investigated steels. The microstructure consisted of ferrite and austenite as well as of precipitates in Fe-18Mn-10Al-0.8C (0.8C steel); while carbides distributed on the austenite matrix in Fe-18Mn-10Al-1.2C (1.2C steel) after the same heat treatment. During deformation, dislocations exhibited a typical paired superdislocation feature in ferrite in 0.8C steel, extensive planar glide occurred in austenite in both steels and Taylor lattice-like structures, and well-developed microbands appeared in 1.2C steel. Overall, 0.8C steel demonstrated a tensile strength of 973.6 MPa and elongation of 44%, and 1.2C steel received a lower tensile strength (881.3 MPa) and a much higher elongation (78%). The strain hardening behavior of the two alloys was also different. The strain hardening rate decreased with strain in a non-monotonic feature for 0.8C steel, while it exhibited a moderate inflection in 1.2C steel. 相似文献
19.
The Fe-B alloy containing chromium and nickel was prepared, and the microstructure and erosioncorrosion behavior of the alloy were investigated by means of scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction analysis, Leica digital image analysis, a hardness tester and an erosioncorrosion tester. Cr28 white cast iron was used for comparison. Results show that the microstructures of both as-cast and heat-treated Fe-B alloys consist of austenite and borocarbide. The nickel and chromium elements are mainly distributed over the matrix and borocarbide, respectively. The hardness of the austenite matrix and the Rockwell hardness of heat-treated Fe-B alloy are higher than those of as-cast Fe-B alloy. In the erosioncorrosion test of the slurry, the erosion-corrosion weight loss of Fe-B alloy is lower than that of Cr28 white cast iron, indicating the Fe-B alloy displays higher erosion-corrosion resistance. 相似文献
20.
为了研制一种铁基耐磨复合材料,采用等离子熔覆技术,通过调节铬含量制备多组Fe-Cr-Ti-C合金系统.借助SEM和XRD等分析手段对熔覆层组织和碳化物形貌进行分析.结果表明,熔覆层中随着铬含量的提高,基体组织由A+F向F及M转变;碳化物M7C3及TiC等硬质相的数量逐渐增多.此外研究了铬含量对熔覆层耐磨粒磨损性能的影响规律,熔覆层的耐磨性随着铬含量的增加而提高,当铬含量达到20.1%时,大量高硬度六边形M7C3复合物结合一定量的呈开花状、球状或团聚状TiC颗粒均匀弥散分布在具有较高强韧性的板条马氏体基体中,使得熔覆层具有最佳的耐磨性. 相似文献