High strength aluminum (Al) alloys were prepared by rapid solidification method in the Al–Ni–La system. Microstructural characterizations show that all the investigated Al–Ni–La alloys are comprised of Al, rod-like Al3Ni, and blocky Al11La3 phases, of which the size and volume fraction are composition-dependent. The Al85.5Ni9.5La5 (at.%) alloy shows the finest microstructure, which contributes to the highest strength along with considerable plasticity. The experimental analysis and finite element simulation (FES) show that the distribution of the intermetallic phases greatly affects the mechanical properties of the alloys. The rod-like Al3Ni phase precipitated with the locally uniform direction prevents the propagation of cracks and benefits the plastic deformation, whereas the blocky Al11La3 phase exhibits the nature of brittleness and acts as the origin of the microcrack initiation. These findings suggest a new method to design high strength Al alloys.

Mg-based metallic glass interpenetrating phase composites (IPCs) containing 30–70 vol% titanium was fabricated in this study. The effects of reinforced phase volume fraction and interspace on the mechanical properties were investigated systematically. With increasing the volume fraction of titanium, the fracture strength and strain increased up to 1860 MPa and 44%, respectively. The results showed that the critical volume fraction (around 40%) of Ti metal should be required for significantly improving plasticity of IPC. Decreasing the interspace of the titanium phase could lead to enhancement of yield and fracture strength. The deformation behavior and strengthening mechanisms were discussed in detail.

A metallic glass/porous tungsten bi-continuous phase composite was prepared by pressure infiltration whose quasi-static compressive stress and strain to macroscopic failure are much higher than those of all the previous tungsten-reinforced metallic glass matrix composites. It deserves to be mentioned that because of its high-yield strength and high elastic strain limit, metallic glass seems to be used as the reinforcement to strengthen the crystalline materials in the bi-continuous phase composite materials.

(Zr62Cu15.4Ni12.6) (x = 6–12) in situ glassy composites containing uniformly distributed Ta-rich particles were prepared by arc-melting and copper mould casting. The results show that addition of 6–10 at.% Ta to Zr62Cu15.4Ni12.6Al10 results in dissolution of 2.4 to 4.6 at.% Ta in the glassy matrix, which promotes glass-forming ability, and the remaining Ta precipitates out as body-centered cubic (BCC) Ta-rich particles dispersed on the glassy matrix. The critical diameters for the composites with 6, 8, and 10 at.% Ta are 7, 7, and 6 mm, respectively. At 12 at.% Ta addition, the glass-forming ability is dramatically reduced because of the precipitation of secondary dendritic Ta-rich particles and other nanocrystallites from melts during copper mould casting. Also, owing to the solid-liquid reaction during induction heating, some Ta-rich particles formed in the master alloys will redissolve into the glassy matrix, resulting in a smaller volume fraction of Ta-rich particles in the as-cast glassy rods than that of the corresponding ingots. The glassy matrix composites exhibit enhanced plastic strain of about 7.5 to 22.5% at room temperature. The optimum Ta content in the glassy alloys is determined to be 10 at.%, which corresponds to the highest ultimate stress of 2220 MPa and the largest plastic strain of 22.5%. The plastic strain increases with increasing volume fraction of in situ BCC Ta-rich particles. This is apparently ascribed to the impedance of Ta-rich particles to shear bands. Ta-rich particles seed the initiation of multiple shear bands and block the shear band propagation, leading to intensive multiplication and bifurcation of shear bands.

The martensitic transformation behavior of FeMnGe alloy (0–6 wt% Ge) was investigated by resistivity and dilation methods. Ge depresses the martensitic transformation of FeMn alloy. The effect of Ge on starting temperature of martensitic transformation (Ms) temperature of FeMn alloy is −12 K/wt% Ge. Comparing Ge (4s24p2) with Si (3s23p2) and Al (3S23P1), which have similar outer shells of electrons, we found that their effects on the Ms of FeMn alloy are completely different. The result suggests that the outer shell of electron is not the main factor governing the Ms temperature of FeMn alloy, although it is essential in the alloy's antiferromagnetic transition.

The processes of rapid solidification from liquid to solid and heating from glass to crystalline for Ni3Al are simulated using molecular dynamics method. An amorphous state can be obtained by rapid solidification as long as the cooling rate is sufficiently large, which is very difficult to get in experiment. An fcc-type crystalline is obtained by heating the amorphous with a small heating rate. Based on the pair analysis technique, the microstructures of liquid, supercooled liquid, amorphous, and crystalline states of Ni3Al have been analyzed. Furthermore, the effects of cooling rate and heating rate on microstructures of Ni3Al during rapid solidification and heating processes have been discussed.

The stoichiometric intermetallic compound NbSi2 has been synthesized by mechanical alloying (MA) elemental Nb and Si powders. The alloying process has been investigated by means of x-ray diffraction (XRD) and differential scanning calorimetry (DSC). It was found that the formation of the Nb2Si intermetallic compound occurs abruptly after 65 min of milling without any interruptions during the alloying process. However, short interruptions at a 5 min interval during ball milling result in a gradual reaction for the formation of the NbSi2 compound as well as a new metastable bcc structured solid solution. We conclude that the temperature rise during mechanical alloying plays an important role in initiating the abrupt reaction after an incubation milling time.

The SiCp/Al nanocomposites were synthesized under high pressure. The reaction behavior between SiC particles and Al matrix within 2–6 GPa pressure range was determined. The high resolution electron microscopy (HREM) observation and the Vickers microhardness measurement show that the reaction is slight and that the adhesion of SiC particles to the Al matrix is good whether the reaction between them occurred or not. This offers an opportunity to tailor the nanocomposite mechanical properties by adjusting the synthesis temperature, pressure, and volume fraction of SiC particles.

A new method is proposed to prepare bulk nanocrystalline alloys by quenching alloy melts under high pressure. Due to application of pressure to solidification processes, the nucleation rate is increased whereas the growth rate of nuclei decreased with increase of pressure, which makes it possible to obtain bulk ingots with nanometer-sized crystalline grains if appropriate pressure, temperature, and cooling rate are selected. The as-pressure-quenched products are cylinder-like with diameter about 4 mm and height several millimeters. This method can produce dense, free-porosity bulk nanocrystalline alloys with clean crystalline interfaces, promising use for experimental research and technological applications.

The microstructure and the mechanical properties at room and high temperatures of monocrystalline Ni3Al containing 0, 0.52, 1.37, 2.22 and 3.00 at%B have been studied. The results show that the ultimate and yield strengths at 20°C and 800° C of monocrystalline Ni3Al obviously increase with the increase of B content, and reach maxima when B content is 1.37 and 0.52 at% respectively. With further increasing the B content to 2.22 at%, they slowly drop. The tensile ductilities at 20°C and 800°C of monocrystalline Ni3Al when the B content is 0 and 0.52 at% respectively are the best in five kinds of Ni3Al studied, then they continuously decrease with the increase of B content due to the precipitation of boride eutectic. The rupture life and elongation at 850°C and 100 MPa markedly drop as the B content is raised in the monocrystalline Ni3Al, but they are still higher by 1 to 2 orders of magnitude as compared with those of polycrystalline Ni3Al with the same compositions. When B content exceeds 1.37 at%, the eutectic structure of Ni20Al3B6 and Ni3Al is formed, which is enhanced by the B content and is harmful to the strength and the ductility.

The alloying effects of Cr, Zr, Ta, Nb and B on the microstructure and properties of single crystal Ni3Al alloys have been studied. The strength of the alloys has been improved markedly with promising plasticity. The 0.2% yield stress of some of these alloys is higher than that of IN713C, a typical cast nickel-base superalloy, in the temperature range from 25 to 950°C and some of them reach the strength level of advanced cast nickel-base alloys such as IN100 in the high temperature range. The creep strength of these alloys is also improved markedly. The single crystal Ni3Al alloy with a high Cr content ( 7 at-%) obviously shows an intermediate temperature low plasticity behavior. Although heat treatment can only slightly improve the strength, it can double the elongation of the alloy from 25% to 50%. In the Ni3Al monocrystal containing 1.2at%Zr there exist great amounts of the low melting point Ni5 Zr-γ eutectics around the ordinary γ/γ′ eutectics. This makes it difficult to homogenize the coarse casting structures completely.

A series of cast Ni3Al-base alloys with the addition of alloying elements, such as Hf, Zr, Ti, Nb etc., have been studied, in which the total amount of Al and alloying elements substituting for Al was controlled in the range of 18 to 23 at%. It was found the alloying elements change remarkably the morphology, distribution and amount of γ phase as well as the morphology and size of primary γ′ intermetallic compound. The size of primary γ′ can be decreased to micron order. The brittle γ′-γ′ boundary (refer to primary γ′) can be substituted by tough γ′-γ-γ′ boundary. As a result, the mechanical properties of the cast Ni3Al-base alloys, especially high temperature ductility, can be enhanced. In addition, the effect of Cr is discussed when tested in air environment, and considered that chromium addition is not very effective to improve the high temperature embrittlement.

Surface alloys with various compositions of Co, Cr and W on 20CrMo steel have been processed by controlling the ratio of thickness of plasma sprayed Co-Cr-W coating to laser melting depth. A formula has been suggested to evaluate the contents of surface alloying elements. With increasing the contents of Co, Cr and W in the surface alloy system, two hardness peaks occur at about 17Co7Cr3W and 52Co22CrgW corresponding to microstructure of M and γ-Co + M23C6 respectively. Wear experiments in media of air, 1N H2SO4 and 1% NaCl indicate that 17Co7Cr3W surface alloy has higher wear resistance in air, while 52Co22Cr9W better in the corrosive media under high load. In any case, wear resistance of the above two surface alloys are much better than that of plasma sprayed coating of Co-Cr-W.

Laserglaze with appropriate post heat treatment has improved the thermal fatigue resistance of a wrought nickel-base superalloy. It was found that laserglaze was able to eliminate the blocky MC phase, refine grains and form a very interesting microstructure of serrated grain boundaries. Careful selection of post heat treatment markedly increased the strength in the laser irradiated region. The initiation and propagation of thermal fatigue cracks were suppressed by this novel microstructure.

Influence of laserglaze on the microstructure and wear resistance of a cast nickel-base superalloy has been studied, which contains very high contents of refractory metals (Mo 33 wt%, W 17 wt%). After surface treatment by laserglaze the alloy structure changes extraordinarily. This change of microstructure enhances the alloy properties. Hardness of the laser melted region is evidently increased, and wear resistance and and corrosion resistance are also improved.