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通过对不同温度固溶处理的FGH95合金进行组织形貌观察及持久性能测试,研究了组织结构对合金持久性能及其断裂机制的影响。结果表明:经1150℃固溶和时效处理后,合金中有粗大γ′相在较宽的边界区域不连续分布,其周围存在γ′相贫化区;经1160℃固溶及时效处理后,合金中粗大γ′相完全溶解,在晶内弥散分布高体积分数的γ′相,并有粒状(Nb,Ti)C碳化物在晶内及沿晶界不连续析出;经1165℃固溶和时效后,合金的晶粒尺寸明显长大,并有硬而脆的碳化物膜沿晶界连续析出。在650℃/1034MPa条件下,经1160℃固溶和时效的合金,由于在晶界处不连续析出的粒状碳化物对晶界具有钉扎作用,可有效阻碍晶界滑移,使合金具有较好的抗蠕变性能。合金蠕变后期的变形特征是晶内发生单取向和双取向滑移,随着蠕变进行,滑移迹线增多,并在晶界处引起应力集中,致使裂纹在晶界处萌生及扩展并最终导致断裂。
The effect of microstructure on the ductility and fracture mechanism of the alloy was studied by observing the microstructure and durability of FGH95 alloy solution treated at different temperatures. The results show that after solid solution treatment and aging treatment at 1150 ℃, the coarse γ ’phase in the alloy is not continuously distributed in the wider boundary region, and γ’ phase depletion zone exists around it. After solid solution treatment and aging treatment at 1160 ℃, The coarse γ ’phase is completely dissolved in the alloy, and the high-volume fraction γ’ phase is dispersed in the grain. The granular (Nb, Ti) C carbides precipitate discontinuously in the grain and along the grain boundary. After aging, the grain size of the alloy obviously grows, and a hard and brittle carbide film continuously precipitates along the grain boundary. Under the condition of 650 ℃ / 1034MPa, the solid solution and aging alloy at 1160 ℃ have the effect of pinning grain boundaries by the discontinuous precipitation of granular carbides at the grain boundaries, which can effectively hinder the grain boundary slip and make the alloy more stable Good creep resistance. Late deformation characteristics of the alloy creep is the occurrence of unidirectional and double orientation slip within the grain, with the creep, the slip line increased, and the grain boundary caused by stress concentration, resulting in cracks in the grain boundary initiation and expansion and Eventually leading to rupture.