The structure,morphology,hardness,breaking toughness,high-temperature yield strength,strengthening and toughening mechanism of the RE/MoSi2 composites were investigated by means of X-ray diffraction(XRD),scanning electron microscope(SEM),Vichers hardness tester,electrical omnipotence material tester and dynamic heat simulate in this paper.

The mechanism of strengthening and toughening of crack-free Fe-based alloy with high hardness for laser cladding;

The authors review some research results of ceramic matrix nanocomposites both at home and abroad in recent years, including mechanical properties and their factors, uniform dispersing of nano particles and mixed with ceramic matrix, shape forming of the materials, its structure, the mechanism of strengthening and toughening.

The paper introduces its concept,types and characteristics about an-quenched and an-tempered steel,and sum- marizes the application of un-quenched and un-tempered steel for sucker rod developed in China,then analyses the mechanism of strengthening and toughening.

In this paper,toughening and strengthening mechanisms of nano-composite ceramics are introduced,the main factors affecting the mechanical properties of the nano-scale ceramic composites are discussed.

Toughening and strengthening mechanisms of nano-composite ceramics were introduced,the main factors affecting the mechanical properties of the nano-scale ceramic composites were discussed.