研究了液相烧结钨基高比重合金(95W-3.5Nj-1.5Fe)烧结后热处理对力学性能的影响.经过1200℃真空热处理,合金中氢含量降低了70%,强度提高约30%,延性显著增加,同时断裂韧性值也有提高。通过扫描电镜断口金相观察,发现氢含量高的试样显示了基体-钨颗粒相界面断裂,对氢含量低的试样,断口微观形态由沿相界面断裂方式过渡到相界面断裂和部分钨颗粒解理断裂方式,说明削弱了氢脆,加强了相界面结合力,从而改善了合金的力学性能。对氢含量高的试样,作了离子探针分析,其结果指出钨颗粒周围含氢最较高,相界面有氢的富集,它是导致相界面断裂的根源。
The effect of post-sintering heat treatment on the mechanical properties of a liquid phase sintered tungsten-base ahoy (95W-3.SNi-1.5Fe) has been investigated. Through heat treating in vacuum at 1200℃, the hydrogen content of the alloy was decreased by 70%, however, its strength was increased by 30%, and its ductility and fracture toughness were also improved. A SEM observation on the fracture surface of the alloy showed that interfacial failures occurred at the tungsten particle-matrix interface in specimens with higher hydrogen content. While in specimens with lower hydrogen content, the fracture mode were transfered from interfacial to interfacial plus partly cleavage failures in tungsten particles. It appears that the hydrogen brittleness is diminished, and the cohesion of the interfaces increased, as a result of decreasing the hydrogen content of the alloy. Ion microprobe analysis showed that in specimens with higher hydrogen content, hydrogen is concentrated at interfaces, which further accounts for the influence of hydrogen on the interracial failure of the alloy.
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