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In this work, surface modification of a Mg-4Sm-2Al-0.5Mn alloy with high current pulse electron beam (HCPEB) under different number of pulses were investigated. The evolution in microstructure, composition and phase components and properties in the surface layer before and after HCPEB treatment were characterized. It was found that the Al11Sm3 and Al2Sm phases in the surface layer were gradually dissolved during HCPEB treatment, leading to the formation of a chemical homogeneous melted layers. Besides, deformation bands were formed in the treated layer due to the thermal stress generated during treatment. After 15 pulses treatment, the surface hardness increases to the maximum value of about 62.2 HV, about 61.2% higher than that of the untreated state. Electrochemical results show that the 15 pulses treated sample presents the best corrosion resistance in the 3.5wt% NaCl water solution by showing the highest corrosion potential (Ecorr) of -1.339VSEC and the lowest corrosion current density (Icorr) of 1.48 × 10−6 A·cm−2. The results prove that the surface properties of the Mg-4Sm-2Al-0.5Mn alloy can be significantly improved by the HCPEB treatments under proper conditions.

In the present study, the effect of high current pulsed electron beam (HCPEB) surface treatments on the microstructure, composition, stress states and properties of a Mg-8Gd-3Y-0.5Zr alloy has been investigated. The surface layers showed different features in microstructure and residual stress states under different number of pulses. Such a variation is essentially due to the different level of the dissolution of β-Mg5(Gd,Y) particles in remelted layers and the impact from thermal stresses generated by HCPEB treatments. The results have shown that, after 5 pulses of HCPEB treatment, maximum hardness in the surface layer of the sample was increased by 35% and the corrosion rate in 3.5 wt% NaCl water solution was reduced by 30% as compared with those of the untreated sample. The formation of nano structured cells of Mg-RE solid solution and β-Mg5(Gd,Y) nano precipitates, together with the residual compressive stress in the surface layer of the 5 pulsed sample account for the increased microhardness and improved corrosion resistance of the HCPEB treated Mg-8Gd-3Y-0.5Zr Mg alloy.

In this work, a novel low cost and durable geopolymer based rapid repair material (RRM) with hydrophobic surface and high strength was proposed derived from fly ash, ground granulated blast furnace slag (GGBS) and rice husk ash (RHA). The experimental results show that RRM exhibits 142–212 mm flow diameter and the less setting time 35 min, resulting in a higher early compressive strength and bonding strength. In addition, the increased contact angle (from 25° to 92°) of RPM indicated the complete surface hydrophobic modification, which contributes to higher waterproof properties and chloride permeability, stronger freeze-thaw and surface abrasion resistance. The RPM developed in this work show significant potential in rapid repair concrete materials.

In this work, new foamed thermal insulation geopolymer composite based on polystyrene particles (PP) and metakaolin was developed. Compressive strength, flexural strength, high temperature resistance and microstructure were evaluated. The experimental results show that compressivestrengthand flexural strength of the thermal insulation geopolymer composite decrease with increasing polystyrene particle content. However, it still exhibits considerable and sufficient strength. The dry density and thermal conductivityalso decrease as polystyrene particle content increases due to the contribution of polystyrene particles with low density. The floatation of the thermal insulation geopolymer composite on water surface indicates the relatively low density and a good quadratic function relationship can be found between thermal conductivity and dry density. Furthermore, the dense interfacial transition zone indicates the high compressive strength and flexural strength of thermal insulation geopolymer composites. The cumulative intrusion volume corresponding to the porosity decreases and the critical pore diametersshift to lower values with addition of polystyrene particles. Geopolymer composites gain strength after exposure around 400 °C, and it suffers dramatic strength loss after 800 °C temperature exposure especially for the 100% polystyrene particles addition specimen.

Single α-cordierite glass-ceramics for low temperature co-fired ceramics (LTCCs) substrates were prepared successfully from perlite as the basic raw material. The glass-ceramics could be highly densified above 850 °C and the α-cordierite being the only crystalline phase precipitated from the glass power sintered within 900–950 °C. With increasing sintering temperature or sintering holding time, μ-cordierite was effectively transformed into α-cordierite, and completely transformed into α-cordierite at 900 °C for 6 h. The synthesized single-phase α-cordierite glass-ceramics possessed low dielectric constants (5.6–6.1), low dielectric losses (0.0019–0.02), appropriate flexural strength (112–117 MPa) and suitable coefficients of thermal expansion (2.56–2.91 × 10 − 6 K − 1 ), which qualify them as a potential material for LTCC substrates application.

In the present study, the surface microstructures and in-vitro corrosion resistance of an as-cast WE43 Mg alloy after high current pulsed electron beam (HCPEB) treatments are investigated. It is shown that the surface presents craters and wavy morphology after HCPEB treatments, which are the typical characteristics of the morphology after rapid melting and cooling. The initially existed Mg14Nd2(Y,Gd) particles are dissolved, and the fine β՛ (c-bco, a = 0.64 nm, b = 2.223 nm and c = 0.521 nm) precipitates are formed and homogeneously dispersed in the treated layer. The electrochemical measurements in the simulated body fluid (SBF) show that the corrosion current density (Icorr) of the 15 pulsed sample (2.66 × 10−5 A cm−2) is reduced by an order of magnitude compared to that of the untreated sample (1.91 × 10−4 A cm−2), and the polarization resistance (Rp) is increased by 176.9%. The disappearance of second phase, the formation of homogeneous dispersed β՛ nano-precipitates and the chemically homogenized melted layer account for the improved corrosion resistance of the 15 pulsed WE43 sample in SBF.