The excellent mechanical properties of powder metallurgy (P/M) superalloys strongly depend on the microstructure, such as grain size, and morphology and size distribution of the ␥ Ј precipitates. The microstructure is, in turn, determined by the heat treatment, viz., solution annealing, quenching, and subsequent aging. To study the effect of the quenching process, two types of quenching methods were used to produce different quenched microstructures in a UDIMET 720LI (U720LI) alloy. One was a continuous quenching method, where samples were cooled along linearly controlled cooling profiles, each at a fixed cooling rate. This test studied the effect of cooling rate on the size of cooling ␥Ј precipitates (formed during quenching) and the consequent strengthening effect. The other test was the interrupted quenching test, which allowed tracking the growth of cooling ␥Ј precipitates with decreasing temperature during quenching at a given cooling rate. The strengthening response at each interrupt temperature was also studied. Results from the continuous cooling tests showed that the relationship between the size of the cooling ␥Ј precipitate and the cooling rate obeys a power law, with an exponential being about 0.35. The tensile strength was found to increase linearly with the cooling rate. Strengthening due to the subsequent aging treatment occurred regardless of cooling rates. The interrupted cooling tests showed that ␥ Ј growth is a linear function of decreasing temperature for a given cooling rate. A nonmonotonic degradation of tensile strength against interrupt temperature was discovered.

Juvenile nasopharyngeal angiofibroma (JNA) is a rare benign tumor arising predominantly in the nasopharynx of adolescent males. It is an aggressive neoplasm and shows a propensity for destructive local spread often extending to the base of the skull and into the cranium. Clinically, however, it is obscure with painless, progressive unilateral nasal obstruction being the common presenting symptom with or without epistaxis and rhinorrhea. Diagnosis of JNA is made by complete history, clinical examination, radiography, nasal endoscopy and by using specialized imaging techniques such as arteriography, computer tomography and magnetic resonance imaging. Histopathology reveals a fibrocellular stroma with spindle cells and haphazard arrangement of collagen interspersed with an irregular vascular pattern. A case report of JNA with rare intra-oral manifestation in a 17-year-old male patient is presented in the article. JNA being an aggressive tumor may recur posttreatment. Thus, early diagnosis, accurate staging, and adequate treatment are essential in the management of this lesion.

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