W, Co, Ni对时效合金强度和韧性的影响

研究了Ｗ，Ｃｏ，Ｎｉ对时效合金强度和韧性的影响。结果表明：高Ｃｏ的ＦｅＷＣｏ合金有强的时效硬化能力，但其韧性较低。以Ｎｉ取代部分Ｃｏ之后，合金的韧性得到大的提高。ＦｅＷＣｏ合金的Ｃｏ量约２３％，Ｗ，Ｍｏ总量超过１８％时，硬度增加甚少，韧性损害较大，而ＦｅＷＣｏＮｉ的Ｃｏ当量达２３％，Ｗ，Ｍｏ总量达２４％时获得最佳的强度和韧性的配合。萃取化合物的Ｘ射线衍射（ＸＲＤ）分析表明，时效合金的主要金属间化合物是Ｆｅ３Ｗ２型，还有Ｆｅ７Ｗ６和Ｆｅ２Ｗ型化合物。淬火态、退火态萃取物的化学分析表明，时效合金中，Ｗ，Ｍｏ主要存在于化合物中，而Ｃｏ，Ｎｉ主要存在于固溶体中。时效硬化主要通过Ｗ，Ｍｏ金属间化合物的析出引起。而Ｃｏ，Ｎｉ主要通过影响析出相的数量、析出物形态及分布状态来影响时效硬化。

INFLUENCE OF W, Co, Ni ON STRENGTH AND TOUGHNESS OF AGEING ALLOYS

The influence of W, Co and Ni on strength and toughness of ageing alloys was studied. The results indicated that the FeWCo alloy with higher cobalt possesses stronger ability of agehardening but lower toughness. After cobalt is partly substituted by nickel, the toughness of alloy is greatly raised. The hardness almost doesn't increase and toughness decreases greatly, when the total content of (W Mo) is over 18% in FeWCo alloy with 23% Co, but when the cobalt equivalent reached 23% and the total quantity of W and Mo reaches about 24% in FeWCoNi alloy, the optimum combination of strength and toughness is obtained. Xray diffraction (XRD) result for extraction compounds showed that Fe3W2 type is the main intermetallic compound in ageing alloy, and there are also compounds of Fe7W6 type and Fe2W type. The chemical analysis of extraction compounds showed that the majority of W and Mo exists in compounds, while the majority of Co and Ni exists in solid solution. The agehardening is mainly caused by depositicompounds of W and Mo. Co and Ni have an effect on agehardening mainly through affecting quantity, shape and distribution of precipitation phases.