Daqian SUN
,
Zhenan REN
,
Zhenfeng ZHOU
,
T.North
,
Yang ZHAI
,
S.Sathian
材料科学技术（英）
Microstructural features of friction-welded Ti-6Al-4V joint have been investigated by both optical microscope and transmission electron microscope (TEM). The microstructure of the welded joint is not uniform. It can be classified into the phase transformed region(P), the deformed region(D) and the region of unchanged base metal(B). In the phase transformed region, the microstructure consists of platelike, acicular and equiaxed alpha phase plus beta phase between them and the dislocations can be observed in some or phase particles. The equiaxed alpha phase mainly distributes in the near center of rod specimen. The quantity of platelike and acicular alpha phase and the size of the grains increase progressively along the radial direction of the rod type welded joint. In the deformed region, the grains are reoriented and the microstructure consists of the elongated alpha phase containing a lot of dislocations and intergranular beta phase.
关键词:
Jingfei LUAN
,
Ji
,
ong HU
,
Zhenfeng ZHOU
,
Hongying WANG
材料科学技术（英）
Using electrode as laser cladding materials, the microstructure and wear resistance of laser-clad layer of ductile cast iron was studied. The laser-clad layer can be subdivided into the melted zone where existed large amounts of austenite, graphite nodules and some carbide, and the solid state transformation zone which included martensite and austenite below the melted zone. The Ti combined with C to form TiC, increasing the wear resistance. The Co significantly increased the wear resistance compared with Ti.
关键词:
Daqian SUN
,
Zhenfeng ZHOU
,
Wenquan WANG
,
Lian LIU
材料科学技术（英）
The effects of Si, Mn and Al on the microstructure and mechanical properties of ADI weld have been studied. The microstructure of ADI weld metal mainly consists of bainitic ferrite and retained austenite. Mechanical properties of ADI weld increase with increasing Si content, but an excess of Si(3.79%) results in decreasing the austemperability owing to decreasing the carbon content of the matrix austenite. Mn increases the retained austenite volume fraction, but the ductility and impact toughness of weld obviously decrease with increasing Mn content because of increased amount of martenite and twin martenite. In the range of 0.13%~0.64%, increasing Al content favours improving the mechanical properties of ADI weld. Therefore, it is very important to select suitable Si, Mn and Al contents to improve mechanical properties of ADI weld.
关键词:
ADI weld metal
,
null
,
null
