IS CHER REALLY GOING HEAVY METAL? She's teaming with rocker Jon Bon Jovi for her first album in five years. Bon Jovi will help with songwriting and will join Cher on a remake of ``Bang Bang,'' her 1966 hit with Sonny Bono. VLADIMIR FELTSMAN, Soviet pianist, arrived in the United States on Tuesday with his wife and young son, successfully ending an eight-year-long emigration effort. He plans to teach at a New York state college, and recitals are in prospect. FRENCH AND AMERICAN IMPRESSIONIST PAINTINGS will be sent for a six-month exhibition in Japan in 1989. The Springfield (Mass.) Museum of Fine Arts will preview its first international exhibition at its own quarters in the fall of 1988. FILMS FROM FOUR WOMEN DIRECTORS are among those scheduled at the third annual Boston Film Festival, Sept. 17-24. The films are ``The Mozart Brothers'' (Suzanne Osten of Sweden); ``Sorceress'' (Suzanne Schiffmann); ``I've Heard the Mermaids Singing'' (Patricia Rozema of Canada); and ``Heaven'' (Diane Keaton). A FREE SHOW IN NEW YORK'S PROSPECT PARK is planned Sept. 12, when Bread and Puppet Theater performs an outdoor spectacle with the US Constitution and an Iroquois Indian document as its theme.