Ti-6A1-4V （TC4） alloys were plasma carbonized at different temperatures （900, 950, and 1 000 ℃） for duration of 3 h. Graphite rod was employed as carbon supplier to avoid the hydrogen brittleness which is ubiquit...Ti-6A1-4V （TC4） alloys were plasma carbonized at different temperatures （900, 950, and 1 000 ℃） for duration of 3 h. Graphite rod was employed as carbon supplier to avoid the hydrogen brittleness which is ubiquitous in traditional gas carbonizing process. Two distinguished structures including a thin compound layer （carbides layer） and a thick layer with the mixed microstructure of TiC and the a-Ti in carburing layer were formed during carburizing. Furthermore, it was found that the microstructure and the properties of TC4 alloy were significantly related to the carbonizing temperature. The specimen plasma carbonized at 950 ~2 obtained maximum value both in the hardness and wear resistance.展开更多
This paper deals with the cause of intergranular fracture occurred in the retained austenitic region in plasma carburized layer.The results show that the presence of retained austenite, which has a good effect on the ...This paper deals with the cause of intergranular fracture occurred in the retained austenitic region in plasma carburized layer.The results show that the presence of retained austenite, which has a good effect on the impact toughness,has no relation to this embrittlement.Analy- sis by Auger electron spectroscopy shows that the impurities S and P segregate at the grain boundaries is the main reason of the intergranular embrittlement in carburized layer. However,the segregation of P and S can be removed by reheating and quenching treatment.展开更多
基金Funded in part by National Natural Science Foundation of China(No.51301023)the Fundamental Research Funds for the Central Universities,Chang'an University(No.CHD2011JC126,2013G1311054 and 310831151079)
文摘Ti-6A1-4V （TC4） alloys were plasma carbonized at different temperatures （900, 950, and 1 000 ℃） for duration of 3 h. Graphite rod was employed as carbon supplier to avoid the hydrogen brittleness which is ubiquitous in traditional gas carbonizing process. Two distinguished structures including a thin compound layer （carbides layer） and a thick layer with the mixed microstructure of TiC and the a-Ti in carburing layer were formed during carburizing. Furthermore, it was found that the microstructure and the properties of TC4 alloy were significantly related to the carbonizing temperature. The specimen plasma carbonized at 950 ~2 obtained maximum value both in the hardness and wear resistance.
文摘This paper deals with the cause of intergranular fracture occurred in the retained austenitic region in plasma carburized layer.The results show that the presence of retained austenite, which has a good effect on the impact toughness,has no relation to this embrittlement.Analy- sis by Auger electron spectroscopy shows that the impurities S and P segregate at the grain boundaries is the main reason of the intergranular embrittlement in carburized layer. However,the segregation of P and S can be removed by reheating and quenching treatment.
