Al—Mg—（Sc）合金退火组织和性能

通过金相组织观察、硬度测量、力学性能测试及剥落腐蚀实验，研究了微量Sc对Al-Mg合金显微组织，再结晶温度，力学性能和抗剥落腐蚀性能的影响，研究结果表明：添加微量Sc后，合金的铸态组织显著细化；合金在130℃稳定化退火中硬度基本不下降，在230℃和330℃退火时的硬度下降幅主比未添加Sc的合金在130℃退火时的硬度下降幅度；添加微量Sc后，合金的再结晶起始温度提高到约325℃，而且没有明确的再结晶终了温度，而不含Sc合金的再结晶起始温度为150℃；添加微量Sc后合金从150℃一直到480℃仍然含有大量的变形组织；高温退火后含Sc合金强度较高，在480℃退火后，含Sc合金比不含Sc合金的强度高近70MPa；而且含Sc合金的抗腐蚀能力大幅度提高。     

基于SHS制备Al-Ti-C晶粒细化剂的正交试验研究

利用Al液的高温．使加入其中的Al、Ti、C混和粉末发生SHS反应，制备出了Al-Ti-C中间合金晶粒细化剂。采用正交试验法，研究了Al液的温度、混和料中Al、Ti粉的含量及C／Ti比值对制备的Al-Ti-C晶粒细化剂组织结构的影响．并确定了该细化剂的最佳制备工艺条件，考察了制备的Al-Ti-C晶粒细化剂对工业纯Al的晶粒细化效果。结果表明：当Al液的温度为900℃，Al粉和Ti粉的加入量(质量分数)分别为20％和5％，且混合料中ω(C)：ω（Ti)=1：15时，制备的Al-Ti-C中间合金由块状Al3Ti、粒状TiC和Al基体组成，对工业纯Al具有良好的晶粒细化效果。     

高温合金PCX晶粒细化研究

通过向高温合金PCX中加入CrxNy细化剂,制备了高温合金PCX细晶铸件,研究了CrxNy细化剂对高温合金PCX铸态组织的影响,探讨了晶粒细化的机理。实验表明:与普通铸件相比,细晶铸件晶粒得到明显细化,宏观晶粒度级数由-3.78提高到-1.42;平均晶粒尺寸由1.189023mm降低到0.523747mm;添加细化剂后,一次枝晶主轴长度减少到352.23μm,二次枝晶臂间距由于冷凝条件不变而没有变化;碳化物和显微疏松的尺寸明显减少;碳化物分布均匀,形态由汉字体状和长条状转变为颗粒状和短棒状;细晶铸件显微疏松的数量也有了明显的降低.     

Al-Ti-C中间合金的制造及其细化效果的研究

含有TiC质点的中间合金可以作为铝及铝合金的晶粒细化剂。在试验室内用真空感应炉和电阻炉能够熔炼出Al-Ti-C中间合金。用试制的铸态Al-Ti-C中间合金对99.7％Al进行晶粒细化处理,与商品的丝状Al-Ti-B中间合金比较,有相似的细化效果。这项研究表明,Al-Ti-C三元中间合金是有应用价值的。     

不同C加入量对原位合成TiC颗粒增强钢基表面复合材料组织和性能的影响

为解决金属材料耐磨性与韧性之间的矛盾,以ZG35CrMo为基体,以自蔓延高温合成TiC颗粒为增强体,采用真空消失模铸造工艺制备出表面质量优良的TiC颗粒增强表面耐磨钢基复合材料,对不同C加入量的颗粒增强复合材料的组织和性能进行分析研究.结果表明,制备的表面复合材料分为基体与合金层.当碳粉的加入量为化学计量比4∶1时,复合材料的组织和力学性能较好,加入量过量3∶1时会造成合金层及结合面性能的下降.     

Instability of TiC and TiAl3 compounds in Al-10Mg and Al-5Cu alloys by addition of Al-Ti-C master alloy

The performance of Al-Ti-C master alloy in refining Al-10Mg and Al-5Cu alloys was studied by using electron probe micro-analyzer （EPMA） and X-ray diffractometer （XRD） analysis. The results indicate that there are obvious fading phenomena in both Al-10Mg and Al-5Cu alloys with the addition of Al-5Ti-0.4C refiner which contains TiC and TiAl3 compounds. Mg element has no influence on the stability of TiC and TiAl3, while TiC particles in Al-10Mg alloy react with Al to form Al4C3 particles, resulting in the refinement fading. However, TiC particles are relatively stable in Al-5Cu alloy, while TiAl3 phase reacts with Al2Cu to produce a new phase Ti（Al, Cu）2, which is responsible for the refinement fading in Al-5Cu alloy. These indicate that the refinement fading will not occur only when both the TiC particles and TiAl3 compound of Al-Ti-C refiner are stable in Al alloys.     

Grain refining of flange plate for welded H section steel made under asynchronous rolling condition

Asynchronous rolling technology was adopted for the accumulated ten passes cold rolling, flange plate steel, and for welded H section steel, respectively. The metallographic microstructure analysis, tensile test and annealing test were carried out for cold rolled pieces; thus the ratio of length to width of grain, tensile strength, relationship between the grain size and asynchronous rolling process parameters after annealing can be obtained. The experimental results show that the relationship between the asynchronous rolling and the shearing deformation of rolled pieces can make a reasonable interpretation of the mechanism that asynchronous rolling may improve the strain accumulated energy of rolled pieces and the strength of flange plate steel. This paper provides a theoretical basis for the application of asynchronous rolling in improving the strength of flange plate steel.     

含TiC和TiB2的中间合金细化工业纯铝晶粒的研究

研究了试验室内试制的Al-Ti5-Cl中间合金对于Al99.7(即Ll—工业纯铝)的晶粒细化效果,并把新合金与已经被广泛使用的呈铸态及丝状的Al-Ti5-Bl中间合金在各种铸造工艺参数下的细化效果进行了对比。     

Materials,Metallurgy, Chemistry and Chemical Engineering Microstructure and phase forming process of Al-3Ti-0.2C-1RE grain refiner简

An Al-3Ti-0.2C-1RE grain refiner was prepared by in-situ reaction method. The microstructure was investigated by optical microscopy （OM）, scanning electron microscopy （SEM） equipped with energy-dispersive spectrometry （EDS） and X-ray diffraction （XRD）. The results show that the Al-3Ti-0.2C-1RE grain refiner is composed of α-Al, TiAl3, TiC and Ti2Al20Ce phases. Compared with Al-3Ti-0.2C refiner, the morphology of TiAl3 phase is changed and Ti2Al20Ce phases form with the addition of RE. Accordingly, the refining performance is improved. The phase forming process of the refiner is as follows： Blocky Ti2Al20Ce and fine blocky TiAl3 form in the melt at the initial stage of reaction, then the fine blocky TiAl3 gradually disappears, and the blocky Ti2Al20Ce grows bigger with the increase of holding time. The predominant mechanism to synthesize TiC particles is the reaction between high concentration of solute Ti atoms and graphite particles.     

铸造镁合金的晶粒细化研究进展

介绍了铸造镁合金晶粒细化方面最近的研究进展,指出Al2RE颗粒是有效的形核剂,可用来细化镁-稀土合金和含Al镁合金。其在镁合金中的广泛应用还有待进一步研究。     

Microstruetures and Mechanical Properties of TiC Particle Reinforced TiAl Composites by Spark Plasma Sintering

Using spark plasma sintering（SPS） technique, TiC particle reinforced γ-TiAl composites were prepared with varying weight fraction of TiC powders. The effects of the TiC fractions and distributions on the properties of the composites were investigated. The composite containing 7wt% TiC had the optimum three-point bending strength of 842 MPa,which was 200 MPa greater than that of the unreinforced γ-TiAl intermetallic. The degradation of the bending strength occurred in the composites containing more than 7wt% TiC and this was believed to be attributed to agglomerated particles of TiC, which acted as crack initiation and propagation sites. The increase of strength in TiC reinforced IMCs came from the grain refinement and the interaction of dislocations with the reinforcing particles. The bending strength of the IMC containing 7wt% TiC was theoretically estimated to increase by 85 MPa and 200 MPa, respectively, by the grain refinement and dislocation strengthening, the total of which was ahnost in accordance with the improvement in that of the unreinforced γ-TiAl intermetallic when considering normal estimation errors.