The interfacial reaction zone of SCS-6 SiC/Ti2AlNb composites consists of two TiC layers with fine and large grains,respectively, and a layer of Ti3Si separating the large grained TiC layer with matrix. A discontinuous layer of Ti5Si3 was identified between the two TiC layers. Some Ti3AlC particles distribute within the Ti2AlNb matrix in thermally exposed composites. The formation mechanism of the reaction products was discussed.

Amorphous NiTi films deposited by magnetron sputtering have been studied. The results show that it is easier for precipitation to occur in crystallized films and that, in the films aged at 550℃ for 1h, the parent phase transforms to rhombohedral phase at 27℃ and then to martensitic phase at 2℃.

MoSi2-matitrix composites reinforced with ZrO2 and SiCparticles were fabricated by means of combustion synthesis (CS) com bined with high-energy mechanical milling (MM) and hot-pressing and sintering. The microstructures and mechanical properties of the composites were investigated by X-ray diffractometry (XRD), scanning and transmission electron microsocopy (SEM and TEM), and with a universal meterials testing machine. The results show that SiC particles are mainly distributed inside the grains of the MoSi2s matrix, while ZrO2 particles are distributed at the inter-granular region and produce coalesence and coarseing of the matrix grains during hot pressing. The room-temperature indentation fracture toughness of the composites reinforced with ZrO2 particles non-stabilzed by Y2O3 (the reinforcing agent is coded as OY-PSZ) was higher than that of the composites reinforced with ZrO2 paticles stabilized by 2.5mol% Y2O3 (the reinforcing agent is coded as 2.5Y-PSZ). However, the latter show higher hend strengths. Moreover, the composites hotpressed at 1400℃has a lower hbend strength than hot-presses monolithic MoSi2. It is obvious that there is a synergistic effect of SiC and ZrO2 on the mechanical properties of ZrO2/(MoSi2+SiC) composites.

A detailed investigation on the thermally grown oxide (TGO) layers of EB-PVD thermal barrier coatings (TBCs) on as-coated samples and samples that were thermally exposed at 1050°C for up to 1013h was conducted by using transmission electron microscopy (TEM). It was observed that a mixed layer of alumina and zirconia exists in the as-coated condition. The thickness of this mixed layer remained constant over a long period of time. Thickening of the TGO during thermal exposure is due to the growth of a continuous layer of pure α-alumina caused by inward diffusion of oxygen However, a small amount of increase in thickness of the mixed layer was found in the samples exposed at 1050°C for more than 504h, which is predominantly induced by the aggregation of elements Cr, Co, Ni and the formation of spinels in the mixed layer.